What alternatives are there to OEM?

Situation:
Muffler [a] mounted parallel to and behind bumper on wagon. Mine is good.
Muffler [b] [mid ships] is rusted out where pipe enters it from rear. I doubt it's fixable.
CAT is probably OEM. Longevity is questionable, especially innee and outee pipes.
PA state emissions require all emissions components be installed, but no actual emissions test for pre 96 and only ONE muffler is required.
Friendly & creative muffler / exhaust shop has pipe bender and can custom make almost anything, prices are very reasonable.

Questions
1] Can I use a non OEM CAT? Catalog pictures show much shorter CAT and longer piping than mine. If so, any recommendations?
2] What adverse / beneficial affect [if any] will elimination of mid ships muffler have?
A louder exhaust note is acceptable. As in "mid life crises" and missing my BLMC toys of yester year.

All suggestions / comments are appreciated.

If I left out any data, I'm sure you'll let me know. Spring is here in the NE US - gotta love it!!!

I can't answer your specific questions, but I've got a Timevalve SS system on my 95 wagon from the cat back that I put on in 2000. It was a bit more than factory at the time, but I've not had to touch it since. Cat is still original at 180k miles.

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5

Paul, thanks for the comment.

To the dismay of the purists, I chose the cheap alternative. Custom made "Y" pipe after CAT into rear muffler [no resonator = less restriction] for < $200. As for the decibel level, I can't notice the difference. Of course I'm 62, the sunroof is open and Jimmy Buffett's coming through the CD loud and clear. In all seriousness, there really isn't a noticeable exhaust decibel, nor performance increase.

PS Aftermarket Walker muffler installed was about $425. Corporate restructuring eliminated wife's marketing manager position = no brainer regarding cost benefit ratio.

personally, I would not attempt to 'upgrade' an exhaust on a Mercedes 300. These are not performance cars by nature and any attempt to make them such I believe would be futile..both emotionally and economically...but best of luck otherwise...