if your going to forge it straight off, your going to need more fuel, matter of fact your going to need more fuel with just the kit as well. You need to get yourself an terminator gas tank and dual gt pumps AT LEAST. Then the 60lbs injectors will carry you as far as you can go non-forged, but if you up the boost you will need more injector and possibly a return style fuel system depending on your HP goals. For MAF i would go with a SCT BA-series, works great for me and my mach, and ill never need another on if i go higher. And you say 'tuner' you realize this thing is going to need to be dyno tuned on top of you buying a handheld correct? Also when you forge it your going to have a few hundred bucks wrapped up in just machine work as well. And i would also consider a better clutch (Mcleod RST for me, wiont need another one for a long time) and some tranny build work depending on how you drive it. After all that, your rearend becomes the weak link. pretty much anything over 500rwhp and you need to upgrade your whole driveline. and yes im aware of people that have 7million hp on there stock tranny and rear, but those are special cases where shit just hasnt broke yet. The On3 kit will come in cheaper than most kits, but you still have to source alot of parts, mainly MAF and fuel system, dont forget about those prices. I dont think your looking at the whole picture. If you buy the On3 kit without anything else, you will not a have a running car.
2003 Azure Blue Mach 1 - KB, Suspension, Bolt-ons.