Still on an annoyingly difficult quest for a full system. Anyone used/heard of these people?

http://www.profusioncustoms.com/fiat-coupe-stainless-steel-exhaust/

I've just asked for a quote, we'll see what they come back with...

These guys are a few doors down from my karting track.

They quoted me a 2.5" Cat back system for approx £600. They know their stuff but definitely not cheap.

I got my system done here top gear (powerflow) very happy with it. Mine was from the down pipe back 2.5" inc 100cell race cat and twin exit, £470 from memory. It sounds amazing, lovely deep burble on tick over and screams like a banshee on full chat.
Have a chat with some of the specialists most of them do there own systems now.