Reading this thread has got me thinking about my heater. I've never had experience with a boat heater before, but heard good things about them. I ordered one on my 2012 X-2, and it sucks. There are no pullout hoses and the air coming out of the vents is never very hot.
I looked at my engine plumbing. The supply comes from the front top of the engine, similar to Thrall's location. My return goes back to the top (thermostat housing maybe). I'm thinking about replumbing it into the raw water intake to try getting better flow. I'm a little concerned about returning hot water into my cooling water supply. I'd assume there would be enough lake water coming in to overcome the heater return. I could also install a shut off valve to turn it off during the warmer months. Is this plumbing setup common? Why didn't mine come that way from the factory?
I also noticed heatercraft has a hot tube extendable vent. Just looking at the picture, it looks like it would fit where my large vent under the oberserver's seat. There weren't any dimensions, so I'll call them tomorrow to get them. I'm also wondering why my current vent is so large if it's not extendable. I messed around with it again tonight, but couldn't get it to pop out. Here's some pictures of my vent.