Hey all,
Been a long time since I've been in here but in the interest of passing helpful info on to others I figured I'd save someone enormous time and hassle by posting this up.

Berta failed her "safety" inspection due to a rotted-out muffler. At 260K it wasn't a surprise that she needed one. So, I went about trying to source an OEM or equivalent replacement. Here's what I found:

OEM MB muffler and pipe for 1996- 1997 E300 part # 210.490,25.21
$573.67 plus shipping on ebay. $1800 from the stealer
This was not an option.

Eberspacher 23.395.83 I looked everywhere for this as it was listed as a bolt-on replacement. After muliple emails I found out there are none avail in the US and no way to get one here from the EU except paying an outrageous sum. As an aside, I wrote to Eberspacher about this muffler and asked where to purchase it and was sent a link to their distributor in Michigan. I was excited that I might have found a solution to the muffler issue. Then when I emailed the distributor, they wrote me 2 days later with links to the Carquest and Advance Auto web sites. Carquest must be owned by Advance now, because their site routed me to Advance which only lists a cherry-bomb style glasspack muffler as a "direct fit." I wrote the distributor back to ask if the muffler was available elsewhere and was told basically "Oops, sorry we don't have a muffler for your car." So, no luck...

Bosal: the customer service rep who wrote back was apologetic but informed me that there aren't many 96-97 e300s around anymore so they no longer make the muffler for it. They DO however, make 4 different mufflers for the 98-99 models??? He said the mufflers could be retrofit but he was not sure how much modification would be required. I didn't want to take a chance on buying something that needed hundreds of dollars of fabrication to "git er dun" so I passed on Bosal.

Borla: The aftermarket guy was very friendly but I was not interested in a "sports car" sound from the back of my old diesel, especially at $2K.

Straight Pipe: Not an option in my neck of the woods. Besides the majority of my driving is at highway speed at 3500 rpm. I think a few hours of noise from a stright pipe on the car would make me want to drive off a bridge...

So after more calls and emails, I decided I HAD to go universal. I took measurements:
Factory Box: Approx 8" tall, 9" wide, 15" long with 2.5" inlet and 6-8" downpipe.

I found a few that would fit but the "reviews" mentioned "sounds like a big block" whatever that's supposed to mean. As someone who drove a Chevy with a big block 454, I think this just means it was d*mned loud. So here's what I narrowed it down to...

Dynomax 177633 AKA Hush Thrush 17633- $39 retail not available locally, and some complained about reduced "flow" and noise.
Dynomax 17715- $30 retail, described as "throaty," and loud. No thanks.
Dynomax 17696- $33 retail, available locally from an Advance Auto store but had offset inlet and outlet which I thought could make for install issues since the OEM was a straight-thru design.

Walker/Dynomax 17615- $28 retail, not available locally but shipped in one day. This one was designed as "slighly louder than OEM" and has "reduced back pressure." The inlet is in the center and the muffler is reversible, which I thought would make for a more flexible install. This is what I ordered. It arrived 2 days later. The welds were good and it seemed to be of better quality that the mufflers I installed on my truck a few years ago. It was heavier and while the inlet did reduce diameter inside the muffler, it wasn't by much. I stopped at my local Advance Auto and got a downpipe and an exhaust hanger for $15. I payed the local garage $150 to weld it up and "dispose" of the old muffler.

Thoughts: I did everything I could and spent countless hours trying to go OEM here, because I didn't want anything annoyingly loud and obnoxious, and I didn't want something that looked silly like a fart can under the rear bumper. I also simply could not afford to spend alot on a muffler, especially since our other cars are in need of attention. Having driven the car for a few days, I am very happy with the choice of muffler. Walker/dynomax/thrush has lots of different applications and choices but this basic "turbo muffler" is even more quiet than the one it replaced and it may be my imagination but it does seem a little bit "peppier." I know these mufflers are built to "flow" up to crazy cfms, but my calculations say that my inline 3.0 6 cyl puts out less than 400 cfm, so any complaints about "reduced flow" for the Walker 17615 are probably from people in need of a dual-exhaust configuration. One of these suits me just fine. And oh yeah, there is no drone noise at highway speeds. Hope this helps someone...