I guess I'm against the grain on this one...
If I had a stock Mustang and had to do it all over again I would put the supercharger on it, upper intake, injectors, MAF and a fuel pump...have a nice 11 sec car that drives great. This is of course as long as the motor was in good shape, compression test and leakdown would be the first thing I would do. Then do the heads and bottom end when it needed it.
I went the NA route when I was on the mission for that elusive 11 sec ET which 3 years ago seemed to be much harder to get, after getting the power to go 11's I had to learn how to drive with that power and get it to the ground. It was fun, a lot of fun but I would have went the Supercharger route but my motor was in need of a rebuild so, I did the H/C/I, etc...
Being in CA you have to pass strict emissons right? Just be careful what you buy, the cam will be a big player for you....
You can find used computers for around $75-100 and then get the converison kit from Pro-M that is easy to use, buy a good meter 80mm Pro-M and your done.
The quiet V-2 SQ series is a stronger blower that will make more power, you may want to look into.