Thanks Paul - that was my thoughts, can I ask what silencer you went for? Was it a standard Morgan?
Because I have been playing with Caterhams for the last 30 or so years, I had a spare 6" round Caterham straight through silencer with, by chance, exactly the correct sized pipes at either end. It originally came off a 2l. Vauxhall 16v engined HPC Seven. I had the tail pipe, which had a bend in it for side exit fitting, straightened and lengthened slightly and it was a perfect fit, with a nice burble instead of the aggresive bark that the standard shorter oval silencer had.
Peters experience is most interesting and it will be interesting to see what the cat. fitted to my own Cosworth Duratec, manages to do when it comes up for its' first MoT in the spring. Maybe the mapping is better than Omex, although, interestingly, they blamed the exhaust system that Morgan later fitted after the mapping was done, on the SS + 4's?