I dunno guys... I would think a turbo would definitely be the way to go as well. There's quite a bit of parasitic loss regardless of any supercharger you use and 4 Cylinders can use all the HP it can get. Granted the Supercharger might be easier and even cheaper to buy and set up, I think you would get the most benefit and customization single or twin turbo setup.
Just my 20/1000 of a dollar.