Pro-Circuits, T5's, and FMF's all have what I'd consider a very forgiving powerband. They develop a good deal of torque at lower RPM's than what I've seen from CPI's, Shearers, or even Rockets. This allows for far more sloppy riding. My stock stroke ported shee with T5's developed torque almost 1000 RPM lower than my 4mm ported shee with CPI's. If you're having problems falling out of the band with PC's, then maybe you need a gear change or something, because your problems are gonna be worse going with Rockets.