At the moment I don't think you really need a LSD.

A supercharger is a pretty good option as it gives you a usable power band and pretty good increase in power. However before doing any major engine mods (turbo, super, NA kit, etc.) make sure you research what you're doing. Your reliability is probably going to decrease and you'll need to be prepared to deal with whatever may come up. I'd also look into a turbo kit, however, to see the best option.

What exactly do you plan on doing with the car?






And I don't see why the SiR is anything but a good thing....more choices = customer wins.