Easiest way to do it and to maintain it, as far as I can see, is to make a script that does it for you.

This is just a thought, I haven't tried it.

Buildings give multiplier bonuses, and multipliers can always cause extreme cases. If you want to keep things in check, you could try a <BonusType>Flat</BonusType> for buildings and wonders. Not sure what kind of values to aim for here, but from the top of my head I think a +3 bonus for the very first research building would be fairly balanced, and then increase it by one for every new tier. The building level bonus multiplier should be changed into a flat value too, like +0.25 regardless of tier.

This approach has two backsides I can think of right now. It will require planning or testing to find good values for the buildings. And a flat bonus will remain when the Governor settings are changed, so a lots-of-labs planet would still produce plenty of research even when asked to do only manufacturing (but that might not be so bad actually).

edit: relic bonuses would need tweaking too, and multipliers from space stations as well, and probably more things i forgot about

edit 2: also test tp make sure the game will allow flat bonuses for research, i haven't done it

how about upping maintenance cost for research facilities?

you could also look into nerfing the base research rate for planets.

Did you change how starbases work as well ? If not that would add some multipliers which could be unbalancing 

whats to stop someone from building a bunch of reaserch buildings and then focusing all in wealth?

I looked at an old save to see what kind of research I would have got with flat values.

My main research world had class 12 with 12 population, and it produced 369 research per turn (not great, i know, but just to compare against something)

Raw research is 34.8

8 research labs (tier 4) with additional 45 levels of bonus

Technological capital with 7 levels of bonus

Positive multipliers from racial, tech bonuses, relic and just one starbase for +110%

Game pace penalty -50%

Assuming research labs start at flat 3 with +1 for every new tier, this would give 6 per lab

Technological capital can be.. lets say 20

And each level of bonus (45+7) is 0.25

This would give a total of (34.8 + 8*6 + 20 + 52*0.25)*(2.1 - 0.5) = 185.28

So down to about half. That is still too much imho.

Well after playing over 100 turns, its still easy as hell to gain research.  I have pacingdefs at -75%, made changes to the base buildings rates as I stated above and it still gets redonkoulous on how much research you can make.  I only have 2 main research planets as well...Im still betting, that best bet would be to go in and edit every since tech cost, but good grief...that is almost 300 for each tech tree...I have no idea how to do that easily and quickly...but im thinking that if I were to change those numbers, that would be the way to go...but sheesh...

I made a script to change research costs. It works for me, not sure if it works for others. It's VBscript, so should work under any windows, i didn't need to install anything (new) to get it to run on Windows 8

EDIT: Also check the post below for alternative Research cost formula (fast start, slower middle and end game)

EDIT2: Included "TechDefs.xml" and "PirateTechDefs.xml"

EDIT3: as a result of a post by rspiccaver (https://forums.galciv3.com/467114/page/1/), this script now uses an exponential growth model for the tech cost. GalCiv3 already used exponential growth for research costs, so things are closer to Stardocks design like this, only differance is that you can now choose how fast that research cost grows.

EDIT4: cleaned up the code, improved comments

------- copy/paste everything below this line -------

'Disclaimer: I can't program, so the code is noobish, but it does the job

'The tech cost will follow the same exponential growth that Stardock use for the techs
'The only differance is that you can make that growth steeper or shallower with this script
'How much steeper is your choice, it depends on the number of habitable planets and your tastes
'Much steeper growth is recommended for larger maps with many habitable planets
'A bit steeper is recommended for maps with a handful of habitable planets

'1) Save this as a .vbs file (visual basic script)
'2) Place file into a "My documents\GalCiv3\Mods\xxx\Game" folder, xxx=name of mod
'3) Copy/paste all *TechDefs.xml files into same folder
'4) Adjust EndGameResearchMultiplier to a desired value (a few lines down)
'5) Run script once, it takes a few seconds to do all the changes
'If there were no errors, all techs should have their research costs adjusted

'-----------------------------------xxxx-----------------------------------
'How many times more expensive do you want the END-GAME technology to be?
Const EndGameResearchMultiplier = 20
'-----------------------------------xxxx-----------------------------------

Const NumberOfFiles = 10
Dim FilesToOpen()
ReDim FilesToOpen(NumberOfFiles)
' --- List of files to change
FilesToOpen(0) = "AltarianTechDefs.xml"
FilesToOpen(1) = "DrenginTechDefs.xml"
FilesToOpen(2) = "IconianTechDefs.xml"
FilesToOpen(3) = "IridiumTechDefs.xml"
FilesToOpen(4) = "KrynnTechDefs.xml"
FilesToOpen(5) = "TerranTechDefs.xml"
FilesToOpen(6) = "ThalanTechDefs.xml"
FilesToOpen(7) = "YorTechDefs.xml"
FilesToOpen(8) = "TechDefs.xml"
FilesToOpen(9) = "PirateTechDefs.xml"

Const TechBaseCost = 29
Const DeepestTechTier = 9
Const ExponentialGrowthValue = 0.3715

Const TristateFalse = 0
Const ForReading = 1
Const ForWriting = 2

Dim objFSO, objFile, strText, floatResearchModifier
Dim intPosition1, intPosition2, strLeft, strRight, intCost, intTemp(5)

' --- Preparations
Set objFSO = CreateObject( "Scripting.FileSystemObject" )
intPosition1 = 1
floatResearchModifier = Log(EndGameResearchMultiplier*TechBaseCost) / (ExponentialGrowthValue * DeepestTechTier)

' --- Start
For i = 1 to NumberOfFiles
' ---- Open a file
Set objFile = objFSO.OpenTextFile ( FilesToOpen(i-1), ForReading, False, TriStateFalse)
strText = objFile.ReadAll( )
objFile.Close

' ---- Modify content
'--the loop uses "exit do" to break out when the end of the file is reached
Do
intPosition1 = InStr(intPosition1, strText, "<ResearchCost>")+Len("<ResearchCost>")
intPosition2 = InStr(intPosition1, strText, "</ResearchCost>")

strLeft = Left(strText, intPosition1-1)
strRight = Mid(strText, intPosition2, Len(strText))
intCost = Mid(strText, intPosition1, intPosition2-intPosition1)

'--when the file reaches the end it restarts from the beginning, that turns intCost into a string
if isNumeric(intCost) = False Then
exit Do
'WScript.Echo " pos1=" & intPosition1 & " pos2=" & intPosition2 '-for debugging
End If

'--when a tech cost larger than zero is located, do this
if intCost > 0 Then
'--determine tech tier (by using three averages and then round off to closest integer)
intTemp(0) = Log(intCost / (TechBaseCost*0.9)) / ExponentialGrowthValue
intTemp(1) = Log(intCost / (TechBaseCost)) / ExponentialGrowthValue
intTemp(2) = Log(intCost / (TechBaseCost*1.1)) / ExponentialGrowthValue
intTemp(3) = Round((intTemp(0)+intTemp(1)+intTemp(2))/3, 0)
'--determine if research has + or - 10% to it by comparing the three cases to the calculated tech tier
If ABS(intTemp(3)-intTemp(0)) > ABS(intTemp(3)-intTemp(1)) Then
If ABS(intTemp(3)-intTemp(1)) > ABS(intTemp(3)-intTemp(2)) Then
intTemp(4) = 1.1
Else
intTemp(4) = 1
End If
Else
intTemp(4) = 0.9
End If
'--tier and modifier are now known, calculate the new research cost and round down
intCost = Round(intTemp(4)*TechBaseCost*EXP(ExponentialGrowthValue*intTemp(3)*floatResearchModifier)-0.5)
'--replace old cost with new
strText = strLeft + CStr(intCost) + strRight
End If
Loop

' ---- Save the file
'Set objFile = objFSO.OpenTextFile ( "test.xml", ForWriting, True, TriStateFalse) '-for debugging
Set objFile = objFSO.OpenTextFile ( FilesToOpen(i-1), ForWriting, True, TriStateFalse)
objFile.Write strText
objFile.Close
Next

WScript.Echo "Finished"
WScript.Quit 1

Thanks for doing that, Saruboy. Was considering doing it myself, but now I don't have to!

Awesome 

I am honestly very surprised it works. It was my first script. I had no idea how to make one when I started. But with some help from the Google fairy and the copy/paste fairy, it pretty much wrote itself. 

Wow it works!  I figured out what I did wrong and it works...slick as ...err...snot!  Awesome job dude!  Guess you now have a mod you can post if ya want haha!  Thanks so much!  Sending you karma(my first time so hopefully I do that right!)  Awesome job buddy!

Oh right, the generic tree. Should "PirateTechDefs.xml" be in there too? I'll add both, I guess.

Ty for pointing it out.

I'd like to hear how the script is working out in game. I prefer very very slow games. I'd be happy if the research/manufacturing was at 10% or less of normal. Also, I hope you can add this script to the Steam Workshop when 1.1 comes out.

This reminds me. Is there some way to set how long each tech age is? I always think the Age of Expansion is way too short.

I'd like to see the script on steam anyways. More options are always better for power players and I really don't like modding my game manually, I want the workshop to manage them for me.