Mr. Peabody said:
The larger Flowmasters actually flow quite well, and reduce sound significantly without droning.
The bonus is that they sound great.
The problem with them is that they're not particularly well built and tend to fall apart much sooner than they should. I don't know if the SS option makes that any better.
Stainless steel mufflers tend to fall apart faster. Stainless is a weak metal and conducts heat poorly, so the inside gets really hot and the outside stays relatively cool. This is a recipe for cracking.
Racing Beat switched from nice .125 wall/.183 plate mild steel muffler material (HEAVY! but good) to 16 gauge stainless. My brand new muffler cracks pretty much after every event, sometimes after just street driving.
It really comes down to material and way the muffler is made. Plus how the system is isolated and hung from the car all play factors on muffler durability, and well heat.
304 can and does crack...but not always.
409 very rarely cracks or straight up fails. 409 is what the SS that alot of lower end mufflers (Flowmaseter, Magnaflow((polished uses 439)), CherryBomb for the Salute, BlackWidow) use and whats found underneath most modern cars since the 90s. Some euros got factory 304. However 409 does still rust...yet is more malleable.
While SS is really a catch all for various grades of steel, generally speaking, it is not a weak material, and there's something to be said for comparing apples to apples.
.183" or 3/16" is 3 times the thickness as 16 gauge
My FM mufflers would rust out and parts would fall off.
