Roger,
My 4/4 is a 25 year old CVH engine, so a little different to yours, but I have the standard resonator box, still sounds good but great for longer runs with SWMBO.
But I also have a straight through tail pipe for when I'm feeling laddish (some would say loutish) and with this on...it roars!!! I think it improves performance also...but no proof.
its literally a 5 minute job to switch them over with the added benefit that you can really get them clean and shiny whilst off the car.
