that's a hard decision, depends on what you want to do and if time or money is an issue
a good turbo kit will probably take a while to get to you upon ordering and is harder to install especially if everything is not exact. + depending on the kit, you'll have to get rid of accessories (ps, ac).
A super is easier install and cheaper. depends on the turbo, but the super will probably have a quicker responce
ur engine will probalby only hold up to ~550hp and turbos will get you there fast. i'd think supers are a little better starting point. you'll have to read up on turbos to see the hassles (turbomustangs.com)
Personally, i'd go for a turbo if i had an infinite supply of money, and a better engine. turbos are just sick.. i'm very afraid of the bov