[street_white180sx]

u know them mani are only cosmetic one of my friends put one on his silvia and the car actually felt slower. you lose torque as well. i rather stick wit the stock manifold. also how cud u set your car on 18 degrees what type of timing light are you using. because i am 100 percent sure the ignition timing is off on your car if it feels sluggish and wont build boost. also an exhaust leak will kill spool time as well. but not that flutter noise u were talkin about thats timing related if i am quite sure.