Okay, I can sorta make a comparison here. I have the Alpine Turbocharger, Yamanko has the Alpine supercharger. The comments below are directly relating to the two Alpine systems, not Turbos or Superchargers in general.
The Supercharger runs at 7 psi, with no intercooling. It is good for 45 HP to the wheels, properly tuned on an otherwise stock motor.
The Turbocharger runs at 9 PSI, with an intercooler, and it was good for 63 HP <b>improperly</b> tuned.
The supercharger should be good for 60 HP to the wheels with 4-1 Headers and a decent full exhaust, CAI and re-tuning (after adding said parts).
The Turbocharger should be good for 100 to the wheels with proper tuning.
The main advantage of the turbo, is that it is easier to make MORE power. More HP is just a few PSI away. Adjust your wastegate/blow off valve and add the proper ammount of extra fuel (proper ECU)
The main advantage behind the supercharger is instant throttle response, and increased power across the whole RPM range.
Main disadvantage to the supercharger is that getting more HP out of the S/C means replacing parts, and possibly a new pulley. The problem you will run into, is that at high boost levels, the supercharger is heating the air so much, more pressure will not produce as much power, and if turned up too much no additional power. The design that alpine uses does not accomidate an intercooler after the supercharger.
The main disadvantage to the Turbo is complexity, and turbo lag. But the alpine kit has no turbo lag problem. I am at 9 PSI at anything above 2500 RPM. The complexity issue is a different story. If the company that designed the kit, had problems tuning it...how well do you think you will fare? To be fair to alpine, they were somewhat rushed due to the fact that they had tickets already booked for a return flight. If they had the ability to keep my car an extra day or two, they could have ironed out a lot of the tuning issues.
Yamaneko has 2 problems with his Supercharger. #1. It keeps blowing off the fuel lines (or they leak) due to increased fuel pressure. Double hose clamps or threadded fuel line connectors would solve that problem. #2. In third gear, the RPM's are so low, the supercharger is only making about 2-3 PSI, so the acceleration (in 3rd, 4th and 5th gears) is somewhat slower than the 18 HP difference between the Turbo and the supercharger would seem to indicate. (keep in mind, the turbo is making the full 9 psi at 2500 RPM).
The main problems I have had with the turbo system are the tuning of it, and the poor quality fittings/bolts accessories that Alpine chose to use. I am slowly tuning it better as time goes on, and I will eventuall spend about $2000 total to scrap the 5th injector, and Uni-Chip in favor of a HalTec ECU replacmeent and 4 larger injectors. I am also slowly replacing the crappy hardware they used, and upgrading it with more reliable fittings, hoses, and the like.
Yamanko and I will be Dyno'ing the cars on October 6th. It will be interesting to see if the Numbers/Dyno charts Alpine gave us match the new Dyno's.
Questions?
Leave it to Random to Needlessly complicate things.