The 4.0 is very strong and will hold up to the turbo or supercharger with no problem. I had the Xcharger Xtreme on my 2006, running 12 lbs of boost. Installed it with 90,000 miles on the car after 2 years of running a 75 shot of nitrous
. When I sold it in June 2012 and ordered the 2013 it had 203,000 miles on it, still running mid 12's. Car is still running strong today. Obviously I used it as a daily driver year round with a 45 mile each way commute, and raced it almost every weekend at the drag strip from May through October.
A friend is running the Powerhouse turbo on his car - something like 20 lbs of boost on the stock motor. Has been in the low 11's and drives it hard at the track.