Try downloading the first version first, if "file not found" or similar errors occurs then download the next version below.
There are many ways you can get the parts on your car to be updated when using this trainer. For simplicity, I have listed out a procedure which I usually follow.
1) Startup NFSU2 and load your profile
2) Enter career mode, select car you want to modify and return to explore mode
3) Activate the NFSU2 Mega TRainer and select the corresponding lot number of your car
4) Change the parts on the trainer and click on "Set Parts Info."
5) Return to NFSU2 and enter any shop and then exit to explore mode
6) Your car should be updated with the new parts/cars
By the way, the savegame directory is
C:\Documents and Settings\[Username]\Local Settings\Application Data\NFS Underground 2
Credits to Override2Zion@CMF (www.2thezion.com)
Thanx for the update Hidea!
Edited by Herby, 21 December 2004 - 17:31.