All depends on your setup that you choose to go with. We like to run the Paxton setup with 10lbs on the gen1's, Vec3 for engine management, and some other upgrades as well. Exhaust, rockers etc.
The horsepower and torque is extremely stout on the Gen1's.
DEFINATELY make sure your head gaskets are in good shape as they are the GEN1's weak spot.
We saw 649rwhp and 702rwtq with a safe 91 octane tune. There could be more with a little more fine tuning as well.
Customer was very happy as the car did run amazing. Had crazy torque from 2500 rpm up.
Todd
A&C Performance
951-696-0500