Buy a used 911, it'll be cheaper if you plan on driving it for more than 3 years and faster without sacrificing much and giving you a comfy interior.
Base 911 from the 997 generation starts at 340 horses, S bumps you up to 380.
Seriously, price out a new car, or lightly used, then go add up everything called out above if you want to do more than look pretty in a parking lot. I bought my car new, I'm currently $30k into the car including initial purchase price and current modifications. If I continue on the path to forced induction I will likely end up spending over $40k on the car and I will be happy with ~240 WHP because reliability trumps numbers for my purposes. Sure you can do it cheaper, knock $10k off by starting used, skipping some of the money spent on tires, suspension, and cooling mods if you're not tracking/autocrossing but you'll still be around $30k when all is said and done (don't forget labor costs).
Meanwhile I could buy this '06 911 S for $37k (asking) and get 380hp along with a much nicer build quality and bypassing a lot of troubleshooting, heartache, time wasted, and $$$ by keeping the car near factory stock.
http://sfbay.craigslist.org/nby/cto/5123467277.html
(and this appears to be outside the problematic IMS years)
I have my reasons for building the car (as I'm sure OP does) but if simple power is your goal there much are easier ways to do it, not to mention just buying a big displacement car in the first place.