You might find a supercharger much (much!) easier to install as a lot less plumbing, ducting, tubing, and exhaust modification will be required. Spools up faster, and produces less heat, too, so an intercooler isn't absolutely required (though it's a good option when you can afford it.) All said and done, the final cost would be about the same though the supercharger unit is more expensive than a turbo. Today's superchargers are compact, they lie flat, and can be mounted anywhere you can gain access to a pulley, and though you will have some parasitic power loss, the only thing you'll feel is a good, strong pull from up front. MB uses them in cars like the SLK, etc. Just a thought.
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David \\ (98 S70 T5SE Black, misc mods (mostly lighting), red calipers) (92 940GLE)