I was taking into consideration the turbo sizes and strength of the block.
I ran 23psi peak boost on my 4G63 block, but had a nice taper. The solid, iron block on an Evo VIII with its strong stock internals could take it, and the twin scroll turbo was a champ.
The N55 twin scroll turbo is significantly smaller...
2012 335i Mineral Gray
M Performance Exhaust/Brakes/Suspension/LSD|Bav Stage 1/AMP||ER CP/IC/DP/OC | Dinan CAI/N55 PWG BIG TURBO|BMWF30.com