With the ATP setup, I started with the gt2860. Too laggy, got a gtx2860. Made NO difference in spool, so I added the puma speed quick spool header and spooled 300 rpm quicker. That boost curve is on the first page of the big turbo thread. I then bought the dhm quick spool kit with the gt2560. It didn't like my elevation and spooled slower than all the others. 7000' sucks. Russ then convinced me to try a gtx2860 again, but with a .52 a/r exhaust housing. That was the ticket. 20 psi at 3600 rpm. My best 3rd gear log with the ATP/ puma setup was about 4800 rpm, both gtx2860. This ended up costing waaaayyy more than I had planned. If I could do it over, I would have got a hybrid turbo and saved 6k. Lol. I has been fun though.