I would go supercharger. That is what I am planning to do in the next few years. Affordable and sneaky.
Turbos are efficient, but they take too long to spool up. Case in point: there is a kid with a Mazda Speed 3 with an upgraded turbo where I live. He races a lot of muscle cars and usually beats them on top end. Thing is he won't race from a stop/dig- he has to be going 60 miles an hour already to have any sort of competitive edge. Even so, I still beat him, but not by a lot. Kinda scary!
After 3 or 4 races while rolling (which I won), I raced him from a stop light just to make it obvious to him that there is no comparison and it wasn't even close. Rather funny and embarrassing for him in my own opinion. Sure enough, he comes flying back up and honking a count down at 60 miles an hour again.
DON'T BE THAT GUY!
But if you do supercharger, you really need to focus on your
suspension, transmission, and launch technique. We have problems launching with the base horsepower... I can't imagine an additional 100-150 horsepower are going to make it easier.
Not to change subjects, but I am actually debating putting an e-locker or other type of dual-use rear end differential in so that I can maintain limited slip for normal driving and have locking capability for straight line racing/track use (might also be good for Winter, too). You might ask some of the 2013+ Shelby guys what they do or research what upgrades those cars have to get the power down to the street.