Eddie - My car weighs 1,890 lbs (stock RS is around 2,250). The car also has brake, suspension and motor upgrades compared to a real RS. My best lap time is 1:17.10 (with lots of room for improvement). I have never had a real RS, but here are my times with other Porsches I have owned:

73 911S 1:24
02 996 C2 1:20
88 944Turbo S heavily modded 1:17.90
96 993 C2 1:22

Tires were R compound for my carbon car and the 944TS and street tires on the rest...