I have a pair of ProMax 300's that I am thinking about lowering to improve holeshot. If I do this the exhaust relief ports on the back top of the middle driveshaft unit would be submerged at idle and low (no wake) speeds. The Mercury owners manual clearly states this is not good. Does anyone make an extension tube - like a snorkel - to alleviate this problem? Or should I just have some sheet metal shop fabricate such an extension?

Thanks, TJ

You should check out Scream & Fly.
http://www.screamandfly.com/