Barry,

DA have a tune pipe, as well "Troybuiltmodels" and "Chief Aircraft Inc" sells cans and headers for DA. It will cast you an arm and a leg, but performance parts for DA are available. I also think "Chip Hyde" makes headers for DA. Most of the models that come out this year like: Aeroworks(their "Quick Build" line) and Aviation models(TOC) have a canister and tune pipe channels build in their models, but unfortunately "GP CAP 232" not one of these models, so you might have to modify your CAP. It would looks like size 40 model with a chrome tune pipe on the belly(well an engine will pick up some power a long the way too), I hope it helps.