GRR builds great stuff, no doubt. But, a pipe that helps all the way across the powerband just doesn't exist. There has to be a trade somewhere, low, mid, top, low/mid, mid/top. All pipes run great at a certain point. The trick is to find the one that is going to run the way you want it to at the RPM you want it to come to life at.
PTR mids=low/mid
CPI/Shearer/GRR+top(for inframes at least)
2:1=low
Those are just a few options, good luck.