Turbo:
Turbos are killer for places where they're appropriate. They make bucket loads of power, don't rely on the crankshaft to run them and they're not that complicated. Problems would be in the areas of heat generation/dissipation, cost and maintenance.
Turbos are run off the exhaust, so they're using wasted power to make more power. That's pretty cool and oddly environmentally friendly. Downside is that running them off the exhaust introduces a lot of heat into the metal bits so they require excellent cooling for both the compressor and the air. Most units will be oil cooled and lubricated, some oil lubricated and water cooled. It varies. The one thing that's certain is that you had better know your stuff when selecting a turbo. The compressor map should see the bulk of your CFM needs in the very core of the peak zone for the pressure you want. Bigger is rarely better with turbos so actually go out and get some help from a pro. Supra guys can probably be helpful there.
Turbo's always cost more primarily because there's a pantload of piping to get them hooked up to the exhaust, get the exhaust back out of the car, and cool the boost and deliver it to the engine.
Used turbo casings are great as you can just have them built with the wheels you need and have a custom turbo for your application. Remember... if the unit is too big you won't see boost till like 3000rpm or higher which sucks pretty hard, especially if you pass 3000 rpm in the middle of a curve with the pedal floored. Boost kicks in all sudden like and you notice the back end swapping places with the front...
Yanking a turbo out of a diesel pickup or tractor may seem like a good idea but it usually isn't.
Turbo's are usually a little harder to tune than a PD or centri blower and cam selection is critical. Seek professional turbo help if you think you might want a turbo.
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