How much would it cost for a basic exhaust ( pipes and muffler )? A mid-level exhaust? The best exhaust system? Explain the difference in quality, performance, and how long each can last.
It all depends. The first thing that's important in picking an exhaust is what metal it's made of. 304 stainless steel is one of the better metals to have and often times they are covered by million mile or similar warranties. 409 stainless steel is cheaper but be warned that 409 is more likely to rust but may still hold a 10 year warranty. Aluminized steel is about as cheap as it gets but it's even more likely to rust than 409 and may have as much as a 3 year warranty from what I've seen. I would estimate most mufflers will set you back around $100-150 for stainless and $50-75 for aluminized. I got my Magnaflow for $90 with some luck at advance auto during a sale.
