Grimmspeed HiFlow Exhaust Manifold Crosspipe 02-05 WRX, 04+ STI, 05+ LGT Customers have seen up to 15 HP INCREASE when combined with our PnP Subaru Exhaust Manifold. The pipe by itself should net around 5-8 HP INCREASE. Boost transition is improved over stock Helps airflow in the mid to high rpm range Fits: '02-'05 and '08-'10 WRX, '04-'10 Sti, '04-'09 LGT, '91-'94 Legacy Turbo, '04-'09 Baja Turbo