Here are some downloads I personally recommend.  If you got any others you think should be on this list, send 'em to me somehow.

Sovereign Lowrider- Looks great.  Here's a pic.
Piranha Lowrider - Looks kinda weird but cool.  Here's a pic.
Stag Lowrider- Looks really weird.  And the pic.
Phaedra Jeepster- Jacked up Clydesdale.  Very cool. Large pic.
Hack76 ver .67- Very useful program for quick modifying of cars.
HEdit and UltraEdit- Hex editors.  Both of these are just trials and run out after a certain period of time.  If you have one that DOESN'T run out, please send it to me!
Dixie horn- Sounds a lot better than the stock one.
Dodge Challenger - Very cool race car.  Here's a pic.
3 Custom Paints - Some new paint jobs. Nothin special but look kinda cool.

I didn't make any of these files, they were made by other people way more talented than me. And don't complain to me if somethin goes wrong with your system. It's not my fault, don't blame me, cause I'm not responsible. For anything. Ever. OK, I made the last one. But I'm still not gonna be responsible if you use it.