headers for sr20det

hello i plan on geting the sr20det and im just planing out everything i will be adding to it

i was wondering what are the best headers for a sr20det

also down pipe size

exhaust size and muffler

also you know that thing that filters out the toxic waste in the exhaust if i were to remove this would i have any hp gain or would it have negitive results such as loud noise etc just asking just curious

thank you

well first, it's an inline 4 so it's "header" not "headers"
second, the sr20det is a turbo motor, so it doesn't have a header at all (unless you mean a turbo manifold, in that case I'm not sure). For the exhaust piping I would go 3", any straight through muffler would work, every import company makes one.

As for the catalytic convertor, if you removed it you would get a slight power gain, but it would be very illegal in about 45/50 states.

The stock Nissan turbo manifold is as good as it gets. No need to upgrade.

thanks fuiot thats what i needed to know

Oh yeah, and about your other questions...make the downpipe and the exhaust both 3" if you're running a turbo(about 2.25 if you aren't) and that "toxic filter" thing is your cat. Don't bother upgrading it or removing it. Your car will become insanely loud and you'll gain about 2hp. Don't bother unless you boost over 15psi...but then again, at 15psi, the cat is the least of your worries.