wikid11

hi, i have just taken the stupid forge pissssh valve off my and put the standard one back on and it sounds great (no sound) except for a stange vibration noise half a second after i button off has anyone come across this and could you explain,
thanks

oh and could anyone point me to any info on exhaust headers for a my99 jdm wrx
i want to know the diameters, my mate just drop off a set from a version 3 sti and i want to no if its worth changing them over

cheers