new turbo tech GTX garret top mount v-band, 28psi built engine, 93 + 50/50 meth injection
old turbo tech T3 .48 a/r garret from 12 years ago, 19psi built engine 93 octane only
I'd have to check but I would say theres around 400 to 500rpm difference in spool and that they would make identical power on pump fuel because you are limited by boost pressure on gasoline and not compressor flow rate.
Not worth the xtra $7000~ for the built engine and expensive turbo just for a little more spool. And then it needs better fuel, we did 440rwhp with Methanol 50/50 injection. So Include that whole system or E85 into the mix if you want over 20psi of boost with these engines safely. Just for an extra 50 to 80 horsepower.. yeah nty. Well technically the skys the limit, I'm just saying for T-25 sized exhaust hole, you aren't going much over 20psi of boost and 450rwhp... it would be silly.
engine is much happier, cooler, and better off with a top mount T3 sized hole, larger turbine, nice big compressor on a cheap journal bearing turbo is ideal. And when the motor blows the turbo can be replaced cheaply.