Lower intake manifold leak

I just found out that I have the infamous lower intake manifold gasket leak that seems to plague the 3400 engine. I've been trying to find more information on this but still have a few questions. I'm going to be doing this myself since I don't really feel like paying the dealer $900 to change a $50 gasket, but I'd still like to know what gasket is the best to use(i.e. actually fixes the original defect). I know GM has an updated P/N for this, but would the fel-pro gasket be a better choice? I've used fel-pro a lot in the past and always had great luck with them.
The second question is how much of a factor dex-cool is in this failure? I'm thinking either way I want to get my cooling system flushed and refilled with the universal yellow stuff.
I have a 99 grand am SE if it matters.
Thanks for any help in advance

Welcome to AF.

The Fel Pro set is a good choice. You do need new lower intake bolts. Napa can order them, the stealership charges twice as much as Napa.

Also check the LI for bad pitting around the front/rear water jackets.
And make sure you have the updated torq proceedure, found here.
3400 SFI LIM Gasket Procedure (http://www.automotiveforums.com/vbulletin/showthread.php?t=688030)

A cooling system flush is a good idea too.

Good Luck