well, here i am, back from the dead, and we're still talking superchagers... :D
Honestly, the gains I had from the supercharger were that of a comparable 4.0L motor. (Non-HO). The torque, and the acceleration were great, but it ended up costing me a hell of a lot of problems and headaches. tuning it, and dialing in the proper a/f ratio was a pain. it never completely ran the way it should have. if i had enough guts to, i would have taken it to a ricer shop and had them tune it, but chances are, it'd still fall out of whack again.
one thing you will notice quickly, is that it's not a v8. as much as you try, and as hard as you tune and modify the engine, it just won't be a v8, and it won't smoke the 4.6L mustang sitting next to you at the traffic light. the old saying is true "there's no replacement for displacement". if you want the v8, go with it. you'll be much more happy in the long run.
running around with the blower on, (when i could get it to run without problems) was nice. throwing my clutch out due to the increase in torque and power wasn't nice, and the wear & tear on the engine internals began to show a lot more after the blower. it wouldn't pass emissions, and frankly, after a while, i started to think that maybe it was just going to end up costing me too much money in the end. that kit was good once, and it is what it is, a first generation prototype. there's most likely been a lot of improvements since the rimmer days. the new kits from avenger and the others have addressed issues such as fuel pumps, intercoolers, and whatever else wasn't part of the early prototypes.
for now, i've taken my jeep back to the way it was. a set of headers, taurus fan, 4.0TB, and that's about it. i like the way it drives. i also like the fact it doesn't break things anymore.
if you're going to put the blower on, go for it. figure up what it'd cost to do the v8 transplant (at least 5k), and save up that money just in case you need more juice.
either way, good luck with it.