The best person to ask about all of this is your local shop/tuner.
Yeah, it is more efficient because you don't get as much power throughout the whole rpm band. Read up on both before you decide which one to go with and make an informed decision. You could probably turbo for cheaper tho. I would say head gasket for sure, you can find whole engine gasket kits for like $120-150 or something, At this point you would be happier to have changed them then have to do it later after your set up. Have funsupercharger is not as good as turbo... it uses more power just to run it. A turbo is way more efficiant. But yeah, as the 1st guy said, so a compression and leakdown. The best person to ask about all of this is your local shop/tuner.