ORIGINAL: Cobra1
How are you going to connect it? Are going to cut out part of the lower unit?
He's probably got one of the models that comes cutout already.
Mosh, I only run the stock outboards, so I've ignored what's happening with pipes. Try one of these places, they will be able to help you:
http://hyperformanceproducts.com/
http://www.grimracer.com/