First off, I owe apologies to the original author of this post, don't even remember which thread it was in. But this is what I copied from that post;
"OK, let's use Barber as an example. This is what I did.
Create a file named VehicleConfig.ini using Notepad. Add the lines
"Indycar":
UpgradeSetting=(6,0,0,0)
Model=3
Model=3 to change the track to a road course config.
Model=1 for an ovalconfig,
Model=2 for short oval.
Don't add anything else to the .ini for now.
I took the installed track files and put them in their own folder to work with.
C:\Users\Guy Moulton\Desktop\rF2 projects\Indytrackpack\Barber\BIRMINGHAM 2014\1.0
this directory is where I put the .mas file to work with.
Use the MAS2.exe (MAS tool) to open the .mas file. For our track, the one you want is BIRMINGHAM.mas in different tracks
obviously this will be different- use the .mas with the name of the layout you want to change.
There is a .GDB in other .mas files, add the VehicleConfig.ini to all the layouts you want to change. Save the BIRMINGHAM.mas
-Use the MAS2 tool to Create Single Cmp Package. Hit the box with the open lid icon on the tool bar.
-Next to <add New Component> box, give the track a name. Barber_Indy
-Next to File hit the file cabinet icon and navigate to where you want the .rfcmp to be and give it a name.
In the File name: field, put your name, hit open.
I know, it makes no sense. You are opening a file you are creating
-in the drop down box, choose Type: Location
-In the MAS Files box add all the MAS files from the directory you created (including of course the .MAS you changed and added
the .ini to)
-Hit Package. Don't install yet.
Poznan Just replace the original two .MAS files with those from the 1.01 update when you create a new component, and ofcourse
the .ini file must be placed in those 1.01 update files.
-Uninstall the original Barber track. I'm not sure how to do this and change the name of the track, so if you have both
installed, the game gets the names mixed up. Now install your Barber_Indy track. "
I was able to change mid ohio, Poznan and a couple of others using this. Maybe original author will find it and maybe add more explanation.