Dean,
We have a 38' 5th wheel and a 2002 HO, like yours. See mods in the sig and pictures in my reader's rig.
I was told that the stock clutch is build for 250hp and not much more; so you'll have to be very easy on it if you add power. Mine slipped the first time I wanted to "show off" ... . my bad!
I liked the EZ as a good first upgrade, but as they say around here ... . add gages first, so you can keep an eye on your EGTs.
The intake and the 4"exhaust will keep the truck run with low EGT's; and make it sound pretty nice.
The F. A. S. S keeps the right fuel pressure and clean the fuel.
I just got the truck back from the shop, but tomorrow I'll tow with it, so I can tell you how it pulls compared to the stock.
If you need any further info on my set up ... PM me.
Csaba