my 84 rabbit is equipped with a CS engine.. should have had a CR from the factory. and im the SECOND registered owner of the rabbit. but i know for a fact that it did get an engine swap.
and most MK2 cars had the same style of intake manifold as you tho. it wasnt CS only, most likely just a particular hose..
as for making it loud, just turbo it. best muffler ever!
if your keeping it n/a, then dont put glass packs on it.. use real resonators. glass packs are SUPER RAPPY on diesels.. my rabbit would start rapping at about 1500 rpms. but that was with tiny stock tail pipe still.. the bigger the pipe you run, the less loud it is, but the more chances for "diesel drone"..
you got the right manifold and downpipe for your chassis right? idk how many times ive seen people try and use mk2 manifolds and downpipes on mk1s, or the other way around..
Mines a mk2, so if most of them had that intake setup, then it makes sense. It will be staying NA (I'll do turbo with a 1.9 m-tdi someday...) I HOPE it's the right manifold and downpipe. It's from an 8V GTI mk2. I also have a 2.25" resonator from a VR6 Corrado, as for the muffler and the 2nd resonator... Not sure yet. I dunno too many people experimenting with resonators and exhaust setups for 1.6 NA's... at least locally were I could hear the differences. I have herd a "turbo" muffler is good as it adds no back pressure.
turbo mufflers DEFINITELY add back pressure..
anything you cant see through, pretty much for sure adds back pressure..
its not going to be too terrible loud since your gonna have ATLEAST 1 resonator.
its when you dont have any resonators that it gets loud as HELL..
turbo mufflers DEFINITELY add back pressure..
I didn't mean a muffler with a turbine inside

I mean a muffler that has a straight through design; One that is meant for use on cars that have turbos were minimal added back pressure is desired.
You might consider a copper pipe "T" for a splitter. Heater hose stands up to hot glycol so it might work here.
Call the dealer? I think I bought one of those a year or so ago for $25 or so.
turbo mufflers DEFINITELY add back pressure..
I didn't mean a muffler with a turbine inside
I mean a muffler that has a straight through design; One that is meant for use on cars that have turbos were minimal added back pressure is desired.
a turbo muffler:

the exhaust still has to go from one side of the muffler, to the other side of it, it enters one tube, exits the other..
they really arent all that good of a muffler in terms of flow capability..
magnaflow mufflers are decent.. stainless, and straight thru. flowmasters also work decent.
I would just make one from some copper fittings (tees and elbows) and some hose close the fitting size and some hose clamps. I made those wierd bypass cooling hoses for the T/D engine that way and it's worked for 2 years now. It doesn't take anythnig special for that breather hose.