My muffler was fully customised to suit the car. He mailed me the end caps, I marked up the pipe locations (4 pipes in a single muffler) and he sent it back all welded.
Certainly more expensive than a mass produced generic size, but that's hardly surprising.
My R32 Exhaust has a Magnaflow muffler in it, if I need generic mufflers then they're usually a safe bet. I've got the Vibrant clamps on the intercooler pipes, just because they're nicer to use than the bolt together ones and not as expensive as a real Wiggins clamp.