You have to be able to tap into the block or hoses and run hose to and from the heat exchanger. Then cut some holes for the hot tubes. Connect electrical for the blower fan.
I went with the 340 pro all inclusive system from Heatercraft. I wanted the ability to have 4 different outlets from the blower.
http://www.heatercraft.com/marine-he...lusive-system/
I got in on a group buy and got a big discount off retail.
I really like the 2nd generation Hot tubes because not only do they look better, but you can close the vents on them.
There's a ton of write-ups on installs, just search for heatercraft install.