Hi, Darcy,
I've run across several modded cars that have very faint braking properties... First, you must find the data folder, if one exists in the car folder in the uncompressed format... if it's a data .acd file, you'll have to uncompress it using the content manager developer mode... which I haven't tried yet.
Let's suppose you can access the normal data folder... there you will find the brakes .ini folder...look for:
[DATA]
MAX TORQUE = 1900
You can increase the max torque # to a higher value, save & overwrite the file, road test the car, make a judgment to readjust or if you're happy, leave it there.. a word of caution... use care in the ABS settings...
Hope this helps