[madmaxx]

The Roush SR "only" generates about 485 hp, the sr/tw is about 520hp and the r is 550hp. The problem with the "R" is it generates all it torque above 4000 rpm. Not very streetable when going from stop light to stop light. The sr develops all it torque very low and the sr/tw is a happy medium. I am sure Wayne will recommend the sr/tw. The only difference between the sr and sr/tw is the camshaft. The r is a little more radical, no electric choke and I beleive single plane intake. I feel it is more for high rpm road racing, give Roush a call or go to their websight and look at their dyno curves. they do not have one for the sr/tw but it mimicks the sr.