If you really want to s/c the sonic, a front mounted centrifugal is the best way to go. If you have enough fabrication skills and are savvy at replacing bearings, you can do it for not too much money. (There is a little misinformation on this thread)
1 - Find a used vortech, rebuild if necessary. Fab a bracket that aligns with the front end accessories (assuming there is room somewhere) with 1/4" and 1/2" steel plates, weld it. Check s/c bracket designs - usually they have pulleys that stabilize the serpentine belt. Buy a properly sized belt.
2 - Run the piping (edit - PVC intake piping will work just fine but not look great). Run oil feed/drain if needed. It would be wise to not run over 5-7 psi doing this anyway, mix/match pulleys and belts till you get about 5-7psi. Intercooler is not needed. If anything use MeOH injection.
3 - Buy a 2 (or 3) bar MAP sensor that matches the vehicle. Tune yourself, or better have it professionally dyno tuned.
In the end, if you can't make that bracket yourself, or at least cut it and bolt it, then have it welded... this s/c idea is not cost effective.
The biggest benefit to having a front mount s/c - if the s/c is broken, or tune isn't right, re-route the intake piping and block off the s/c intake with a screen (keep this piping in your trunk for worst case scenarios). Would take about 5-10 minutes to swap. Car is still driveable.
Problem with a custom turbo setup - if there's something wrong with the tune/piping etc, your car will likely be MIA for a while. Tow it home and let it sit until fixing.
Best solution - buy a car that already has forced induction from the factory.
