Agree with Nils’ assessment of the aftermarket muffler - I had one that was rattly - cut it apart down the middle and it was a straight pipe with holes wrapped in glass fiber.
My 2wd one is a stainless steel version -was on the van when I bought it - not sure where he got it from but it makes the van sound quite throaty - no power increase though from what I can tell.
So this dinky toy aftermarket be good for another 30 years like the Ernst? … I don’t think so.
The version of this that I had on a previous spare engine and that aftermarket muffler was a rattly mess and very rotten inside with a few small holes.
Not sure how old it was but being aftermarket it was a lot less than 30 years old.
So here we go … I figured a final wrap up on my muffler replacement saga is in order, given the interest in this topic by other posters. Which is nice.
Finished it all yesterday, did the test run and happily passed, learnt a lot, I now understand at least one version of the DIY muffler “remove & replace procedure”, from and including the “J” pipe back to the tail pipe.I reckon the fiddliest install procedure was gaining the best re-alignment of the “J” pipe to the adjoining fittings … if I had had three hands, would have been much simpler.
Truth now is, after removal to the workbench and a very close inspection of the old muffler, revealed a faint stamped manufacture date of 08/1998. So the original muffler lasted 1989-1998 so around 9 years, then current one now removed 1998-2021 around 23 years. I need to get out more but family concerns plus COVID lockdowns etc stopped that.
First, check out the final state of the old muffler. I learnt a lot about never ever again attempt to prolong a life by patching a stuffed muffler already in its death throes. On a positive note, going through the motions enabled me for the first time, to learn about its R&R. This helped later for the final assault!
So what was changed was a new Danish “J” pipe, two new donut ring end seals for it, the new ERNST muffler with new topside muffler straps, all new gaskets, new nuts, bolts & washers everywhere with added anti seize applied, and of course the addition of the silicone sealant to all ring seals and gaskets. So I chose to reinstall the existing cat which of course is totally empty, also reinstall the two muffler support brackets, also the correct “syncro” version Danish tail pipe, which I’d previously changed years ago.
I was aware a previous owner had added at both ends of the muffler, six in all steel support braces welded in place between the end flanges and the muffler casing. I’m also aware there’s a hell of a lot of vibration going on to this part of the exhaust system so I figured it would be prudent to err on the side of caution and have similar 6 high tensile steel braces added to the new muffler before install. See some of them in the pics.
First assembly thing for me was to loosely fit in place the “J” pipe without the donut ring seals in … worry about them later when alignments need fine tuning.
Next, it was tough going, but the 6 ton floor jack just managed to lift the weighty muffler assembly into place. HA!
So refitting the shown muffler assembly, I don’t know how others do this, but what worked for me was to loose fit only the leftside muffler bracket using only the bottom bolt so the bracket sags down (helps clearancing), then raising it on the jack, roll the muffler assembly sideways from right to left, then slide up over the sagged bracket till the leading cat flange reaches the “J” pipe flange. Then raise the muffler, fit the rightside muffler bracket, then loosely fit all four bracket bolts, ready for fine tune fit.
While the muffler brackets are still loose, then fit in place the top muffler straps. Leave the straps loose for now, this helps during trial fit and alignments.
In the end, trick I figured was to fit all bolts and nuts of the “J” pipes and muffler brackets & straps, so as to then carry out a trial alignment of the remaining two joints.
Interesting how shifting sideways or raising or twisting the position of one or other component, alters for better or worse the fit of the two remaining loose joints of the “J” pipe at both ends and alignment to the cat flange. Idea being you end up after some trialling with the best achievable joint alignments. I also found during trialling and final fit, very helpful given I don’t have three hands, was to use an ocky strap to tie/hold the “J” pipe about two thirds to the rear so as to retain it in its approx. final position. Without that, makes the alignment much harder, especially more so while applying silicone sealant to both joints and fitting the two donut ring seals in quick succession, before the sealant starts setting.
Follow the silicone sealant recommended procedure, apply sealant as needed to the joints and seals, leave their bolts loose for at least one hour before tightening them somewhat, then don’t run the motor for at least a day, do a final snug up of the bolts before driving.
There’s probably a lot left out here, like being prepared to spend a lot of time with removal/dismantling the existing, inspection/thorough cleaning of all joints of both new and reused components, making and welding the 6 steel braces on the muffler etc etc. Even down to doing a final clean with isopropyl alcohol of all surfaces the silicone seal is being applied to. In the end you can be as fussy or fussless as you fancy I guess. I was simply wanting as perfect an end result as I could DIY achieve and so hopefully a long life and trouble free for this portion of the exhaust system.
Again … I learnt a lot, which in itself is rewarding. I don’t doubt others could do it differently and better. 
While here, I’m curious to learn whether or not other syncros here do have installed the metal heat shield as is seen on mine in the last pic. It can be seen fastened in place below the muffler, located on the horizontal left to right exhaust pipe. Keen to know if everyone reading this does or does not have it in place. Also if you have it, its present condition. In good nick? Falling apart/cracking up/metal fatigue? That sort of thing. As I understand this part is definitely NLA, I repaired mine.
See ETKA schematic .pdf file below. Heat shield is shown at Position # 39. Part # 025 251 631
51.pdf (43.8 KB)
Hope this R&R procedure report is helpful to others. If so, please reply and let me know. We could even compare notes on this topic, that would be nice. 
Ta. Cheers.
What’s next on my TODO list? HA!
Nice work Ken.
My computer shit itself and I have had to reload everything so getting back on forums has been a really nasty issue.
Nice work on the replacement which everyone knows is a terrible job as most bolts are rusted tight. Designed to torture !
Excellent write up Ken, very informative. A job I am avoiding but will have to do it one day!
No, I do not have that heat shield on mine
Thanks Richard for your reply and interest.
Addendum:
