I found a British website on bike MOT's, which says:
"The decibel level will be assessed at the discretion of the tester, other checks are:
The exhaust mountings must be secure and not fouling any part of the rear suspension
The exhaust must not be holed and free from leaks from both joints and box(es)
Replacements units, other than bikes registered before 01.Jan.1985, must have the BSAU 193 stamp.
The Speciality Spares long slash cuts I have are completely unmarked. They are not stamped 'not for road use', nor are they marked BSAU193. Coming from Texas, I understand why they are not British Standards stamped. Surely the UK government cannot ban all exhausts that are not made in this country? Oh, actually....
You see my quandary? MOT on Monday morning, so we'll see.