I've seen both on a dyno, and the EBC is obviously better, but the turbotech does a very good job. EBC sat right on the set boost, the turbotech creeped 2psi over 4000rpm, no spiking though and good boost build. Hard to compare that to EBC though cos they were on different cars with different turbos
I've got the Blitz DSBC spec-R and yeah, very happy with it.