Here are the extra bits that I do when using the rFactor aiw editor to make an aiw file for GTR2.
When driving the main path keep to the centre of the track, the ai cars follow either side of this for the formation lap and do not use the Left/Right paths in Simbin games.
Make a pit position for pit 52 (TeamIndex=51 in aiw file)
Make 3 garage positions for each pit, including pit 52.
Make start location 104 (GridIndex=103 in aiw file)
where you want the safety car to start at the beginning of the formation lap. Make sure this is the opposite side of the start/finish line to the grid.
Make the rest of the aiw as you would for rFactor.
You have to adjust the groove alpha for Simbin games as they use half of the maximum value that rFactor uses, rFactor max is 1.0000, Simbin uses a max of 0.5000 how you graduate the groove up to the maximum level will alter slightly in Simbin games. You can go as high as 0.6400 in Simbin games, but the extra 0.1400 allows for live track technology to darken the groove during races.
I edit the groove alpha with guitarmaen's aiw and cam editor, but as the values roughly need to be halved you could use other programs to do the job, a spreadsheet for example.
Once you have the aiw made, open it with a text editor (i use notepad) and replace these lines....
WorstAdjust=(0.9000)
MidAdjust=(1.0000)
BestAdjust=(1.1000)
With these lines....
GarageDepth=(3.0000)
WorstTime=(0.0000)
MidTime=(0.0000)
BestTime=(0.0000)
WorstAdjust=(0.7500)
MidAdjust=(1.0000)
BestAdjust=(1.2000)
QualRatio=(1.0200)
RaceRatio=(1.0500)
Adjust the GarageDepth so that the ai cars leave their garages ok.
The GarageDepth is in the gdb file for rFactor tracks and in the aiw file for all Simbin tracks.
Once you have the aiw file working in GTR2 make a copy and keep it safe. You may need it again if any mistakes happen in the next bit.
Go back to the rFactor editor and set "Auto altgrid gen follows main". Then go to where you want the teleport section to start and set alt start location 1 (this should be on the same side of the track as the first start location), move to the opposite side of the main path and set alt start location 2, the editor should then set alt start locations 3 to 101, manually set alt start locations 102 and 103 following the same spacing as the rest of the alt start locations.
Save the aiw file, close the rFactor editor and open the aiw file in a text editor, scroll down to the [ALTGRID] section and copy the GridIndex data, now paste it into the GTR2 aiw file as the [Teleport] section.
You need a full teleport section (GridIndex 0 to 103) for Simbin games.
Now adjust the fueluse, I normally multiply the lap length by a value between 12.9 and 13.5 depending on what type of track it is.
If everything as been done properly you should now have a fully working GTR2 aiw file.
Edit: For Race07 / GTR Evo add a time attack position, you can make this in the rFactor editor by setting an aux location (i use aux location 7) and then editing it in a text editor.
[TIMEATTACK]
Pos=(5.085,-6.957,18.940)
Ori=(-0.065,-1.716,-0.000)
This should be placed after the teleport section and before the pits section of the aiw file.