Jamie,
firstly read this about the fundamentals.
http://www.superchargersonline.com/index.php?main_page=page&id=12
Will try to answer your question to a degree. But there is a great thread "blowing the bug" by Joel that not only is ahving his bug superchargerd but he did it the easiest and prefered method -draw through which I have decided to do to my ea81 Brumby powered trike and I've started collecting the bits. Its all happening.
People can correct me if I'm wrong in my explainations.
Turbo gets its propulsion from exhaust gses...so your headers need modifying there to install that part. Turboes are traditionally more suited to high revving engines although they have come a long way in modern engines whereby low down power is achievable. Dont know anything more about turboes.
Supercharging:
There are two systems- draw through and blow through. Both systems cause a fuel/air mixture to be compressed at a pre determined amount (psi). Easily coined the phrases blow through means the air pump (thats essentially all a supercharger is) pumps air through a "sealed" carbie then into the engine. With the 'blow thru' you can use an intercooler whereby the mixture is cooled prior to combustion allowing for more hp and cooler running. This system is more work to set up. You can use a clutch type pulley on the SC with this set up.
Draw through or suck thru is the easiest bolt on power bang for buck. You find a suitable carbie (SU or Dellorto are prefered) and the fuel/air mixture commenced before the supercharger. Then through your engine. you cant use a intercooler with this set up and have to use a fixed pulley on the SC.
Superchargers run off a belt usually off the crankcase but I've seen pics of them running off the genny belt. They need a lot of belt "footprint" so the belt needs to wrap around the pulley more than say a water pump. Best to use a seperate pulley unit. The boost ammount is calculated by a fromula available on the net. just google it. you need a bit of info first. What boost is ideal. whatever you want! But over 6-8 psi things gets hot, standard engine internals become vulnerable to breakage etc. If you want extreme performance go turbo. If you want good performance without revving the guts out of your engine go supercharger.
Seeking say 5-6 psi is where I will go and Joel sort that also in his bug and got it and the performance made him very impressed. For em it willa ssist in towing my van and make up for some power loss from ym auto trans. 30% extra power and torque is about what to expect. and very little drop in economy.
There are many things to consider and "Blowing the bug" should be read....I have about 6 times now to get it clear in my head.
Cost:
You can purchase a Toyota SC12 from the web for around $400, Dellorto carbie say $300-500, two custom manifolds to make (although I am seeking one half of a lynx twin carb Datsun 1600 manifold for between the carbie and the SC with slight mods) say $200, a blow off valve (dont skimp - I've bought a turbosmart one universal 38mm for $300, air cleaner, and pulley mods say $200. pulleys can get from a wrecker.
Mke sure your engine is in good nick, if you havent yet install a large sump and good oil cooler, get info on water injection which can assist the system and read up on thigns like retarding your ignition. I was green as a few weeks ago but all this will come together ok. then ahng onto your hat!!