i guess we dont have many guys running the rs4 on here
I was kinda in the same boat you are.. In fact I think I passed on getting that RS4 from him, nothing about him or the car just my end..
Anyhow I have since picked up a few RS4 3's.. One brand new Cuda RTR from the local hobby shop that was my first after that I just got the BUG BIG TIME..
I have since snagged 2 more up..
One all billet all aluminum which has now become a shelf queen "Purple Murple"
This car has every Aluminum upgrade available, Hpi Hump Pack, Hitec Servos stock Hpi 18 Engine & THS Pipe
And the Cuda
CUda was all stock for about a week, now has a lot of upgrades. Kept the arms stock, CF Upper Plate, CF Front/Rear Shock Towers, Hpi Threaded Shocks, THS Pipe, Hpi 18, Hpi Hump Pack, Hitec Servos..
I'd upgrade the pipe, maybe some more carbon, keep it light or stock stay away from most of the Aluminum parts nothing but added weight and bling..
Hpi makes some really good street tires. Depending on what kind of surface you plan on running on, I would either go with street radials or belted radios or slicks.. Slicks arent worth crap on a dirty or rocky street I know!
Good luck