I have the mbrp installer series, which is aluminum. Not a true catback as it goes from the flex pipes back. True dual 2.5in after that. The kit was 809.00 all in. Sounds great at cold start, and Idle. Can be a bit loud wide open. The tips are 304 stainless and are 4 inch. I'm happy with the kit, just wish it would have came with downpipes back