merk7408

How much of a difference, performance wise, would it be to:

A: Replace stock muffler on my '03 ECSB which is si/so, with a 3" si/so Magnaflow (need part # for closest thing to stock replacement)

or

B: Cut the flange on the stock y pipe, and go into a Magnaflow 12568 2.5" di/do with the true x design.

I did a few forum searches, but couldn't find anything relating to my kind of setup, factory si/so. Basically my concern is the cost/performace aspect. Option A is going to be my cheaper option, but if there is much more performance in the duals, I'll spare a little extra cash.

NO F-BDY BS

Dont believe the hype, I would guess there would be less than a 2hp difference between the 2 setups you listed above, with a max gain of 7 or so rwhp on a stock 5.3. Im a Magnaflow fan, had thier catback on my 04', and thier catback on my 02' Z. Great quality systems, and are really good if you want a more "mature" sound. Im not familiar with the sound difference between the 2 setups you listed. Id say go with which ever one sounds the best to you.

merk7408

If there was a substantial hp gain between the two then I would go with the most power, but if it is minimal, 2-3, then I will go with the cheapest and easiest. I looked under the truck and couldn't determine which would put me closest for just a muffler replacement, c/c, o/o, or c/o. Has anyone replaced the muffler on a si/so setup, and remember which Magnaflow part# you used?