My opinion is that water supplies a more constant, efficient source of heat than exhaust gas. I guess you are adding a heat plate to the bottom of the intake? It's been a long time since thermodynamics class, but with heat tubes from the Fentons, you are depending on heat transfer through the material only...sure the tubes get hot, but how much is actually heating the plate? Water, on the other hand, is actually flowing through the plate under pressure, transferring a constant supply of heat to the intake. It's also a little easier to hook up water heat than working with hard tubing. I've seen a lot of Fenton heat setups, and the heat tubes can clutter things up if not done carefully. Some guys even drill new plug fittings in the rear of the headers so that the tubing sort of stays hidden, you really have to look close to tell it's there.
Either method is better than no heat at all though.
