I've made custom exhaust in my msp'03. It looks like this, straight 2.5" Stainless steel (acid-proof) form j-pipe to Racing-Beat muffler, no catalic converters. There is problem with o2 sensor but i will emulate it with Schottky diode. Also ther is custom intake with ITG foam filter. And there's problem, I deinstall MBC to see boost and what was my suprise when I saw 9-10PSI. Ass you know with that boost ecu take boost cut near 3000-4000rpm. Instaling MBC take no differenc. What can i do with home made method to take out boost-cut??