Re: XR6t Blow off Valves
I had one, Stealth FX BOV, cost me $500 it was fully adjustable from full vent to full plumb back, direct factory replacement.
There is no performance gain, its totally unrelated, its there to aid in reducing where and tear on the turbo. I only replaced mine so I could alter how much noise I wanted. But I got bored with it after a few months and sold it for $300 and replaced my factory one.
The factory plastic bosche thing will do all your daily chores right up to 13psi or so but then you need to invest in an aftermarket one with stiffer piston spring etc.
If your just after one as a toy, save your money, or end up finding out the hard way that its a waste - like I did LOL!