I have a Greddy S2 with about 71,000 miles on it. How long can I expect a Catback made from 304 stainless to last? I ask because there is one for sale in my state in good condition and I am always on the lookout for spare parts at a good deal. Has anybody put a ton of miles on a 304 Stainless exhaust? I do drive my 8 year round so it is exposed to road salt. But so far the SP2 sounds fine, but does show some age around the welds.