You're going to love it. I've put about 50 miles on mine so far, and I'm still chuckling when I drive. There's so much power even on the 80 setting I'm having to relearn my driving with the 6spd. Feels like a totally new truck.
Your early 99 has smaller injectors than the rest of the late99+ so you might not see as much improvement as some of the other trucks, but I think this difference isn't anything to worry about at all.
With the intake, exhaust and tranny you're really pretty much good to go. You'll just need a set of gauges, but I'm sure you knew that.
2002 Arizona Beige F250 Ext Cab Short Bed. 7.3L 6spd 4x4 140k
2" leveling kit, 285/75 Mastercraft AT2's,Napa BFF, DiPricol Pryo/Boost, DP F5 NS/stock/hi/40/80/120/140agg-lope, Toolbox, Audio goodies, IH shiftknob
muffler delete, CCV reroute, AIH/Foil delete,