[TurboKraft]

The Dansk mufflers are heavy, but any muffler with a lot of metal baffling and sound deadening will be heavy.
We have not found any of the Dansk mufflers to fit worth a damn. All 3x were used on all-original CIS engine restorations 1976-84. Each muffler had to be cut between the turbine flange and muffler canister, and rewelded.
The version with the wastegate plumb back was worst. We reused the original pipe that bolted to the WG and re-made the rest into the muffler.

Also, if that's yours in the first photo, it looks like an old B&B muffler that's been modified to have the WG dump into the muffler outlet.