For your question as to what supporting mods to do with the supercharger:
PI cams are a really good idea. You can find them for <$50, and they're probably worth 30+ hp on a supercharged car.
Exhaust. Offroad pipe will be worth a solid 15 hp, maybe more, on a supercharged car. Can be had for <$150.
Simple intake stuff. My sig says cold air intake, but it's actually just a drop in K&N in the stock box, with a custom made 3" tube going from the MAF to TB. Throttle body probably isn't required, but I found a good deal on one ($100 shipped brand new), so I went ahead and got one.
If you are getting a centrifugal blower like Vortech, Paxton, Procharger, etc, go ahead and get a PI intake (<$200). That's probably worth 20 hp or more with a supercharger. My blower mounts in place of the lower intake manifold, so I didn't have to worry about getting one.
All that stuff and an intercooled Vortech at 9ish pounds and through a 5 speed would be good for a solid 350 rwhp, more than enough to keep you entertained for quite a while.
So you are looking at a total of less than $500 extra for supporting mods, yet will get 50-60ish more horsepower than you would without them.