The big difference in the turbos are the turbine wheels; the regular XT has the Mitsubishi TD05 journal bearing and the R version has the Garrett ball bearing. The Blouch rep claimed that the Garret Turbine wheel was larger than the Mitsubishi, and regardless of the R being ball bearing, it wouldn't spool faster. This didn't make since to me since they are both rated at 430hp on Blouch's site. Being Ball bearing, shouldn't the R spool faster versus the regular XT considering they have the same potential power? What's the point of having both turbos?
Since Blouch couldn't guarantee me that the R would spool faster, I decided to go with the proven results of the regular XT. It's a fantastic turbo with great off boost response, spool and pulls all the way to redline. Cobb said I was leaving 20hp on the table leaving my stock intake and stock sti muffler. I'm very happy
Stage 2 overlay:
2011 Sti Top Mount IC
AVO Turbo Inlet
TXS Catted Stealthback
Cobb is working to get my graph (and dyno video!) on their dyno database. Once they do I'll upload a graph that's easier to see, I hate the mustang dyno print outs.