Just a Sneak Peak......

[spareparts]

get out the credit card
http://www.stainlessmarine.com/index...emart&Itemid=1

you can probably start off with just installing thru hull exhaust tips http://www.rexmar.com/page230.html and connecting them to the existing risers with 4" exhaust hose. You will need to block of the stock exhaust Y pipe. To do it right, you need to pull the engine, remove the Y-pipe and install a Mercruiser block off plate

If you haven't already found them, look at Eddie Marine http://www.eddiemarine.com/ and Rex Marine http://www.rexmar.com/productindex.htm