I purchase a magnaflow cat from Gravana Tuning, and i ordered it at 2.5" because I believe thats what sstock on my '04 ecotec sunfire. But I realized that when I buy a new exhaust, it'll probably be 2.25'...Is that an un-manageable problem?
Not one bit, bud. You can go out to the store and buy carbon reducers easily. Or, if you're doing a full stainless exhaust (or just want to keep rusting down to a minimum) let me know and I can make you (2) T304 stainless reducers that can be welded or clamped right on.
Well I think the exhaust I'm going to get is the RK Sport dual exhaust, which is made of that other special kind of steel, can't remember off the top of my head. But my local shop doing the work for me should handle it no problem?
Yeah, they can manage that--it just won't be out of stainless. If it is, I'd be surprised. RK Sport should be using 409 Stainless. It has a lot of carbon in it, but still qualifies as "stainless" by an inch.
Yeah it says 400 series ferritic stainless steel, claims to be a better application for exhausts. Good choice? Bad choice?
Common, inexpensive choice for exhaust companies. Lesser quality SS has a higher amount of Carbon in it (the stuff that rusts.) It still QUALIFIES as a stainless steel, but just isn't as good as the higher quality stuff. It should be fine for you, bud; it's still better than any stock system!