Sweet! You're my #1 fan! How much money did I agree to pay you, again?
You mind posting a link to that kit? I'm wondering what all comes with it, and I'm too lazy to look it up myself. I personally think the e303 cam sounds great, but is a waste of money unless you're getting an outstanding deal on it. There are better OTS cams to be had, even for a stock motor like yours. Also, guys like Ed Curtis, Buddy Rawls, Jay Allen, etc... will all do a custom cam for you for around $325 (what ed used to charge me). Further, I don't think you should bother with a cam until after you have built the rest of the combo. Once you get all of the induction, exhaust, and any forced induction route you plan to go all sorted out, then pick the right cam for that combo.
Other parts to consider with a cam: roller rockers, hardened pushrods, appropriate valve springs, new timing chain, degree wheel (if you don't already have one), fresh lifters if you have a lot of mileage on the old ones, and go ahead and do the intake at the same time since you'll have to pull it for that anyway (unless you have specialized tools).
When I did it, I replaced the H/C/I and headers all at once.
Chris