unless you're going to get the newer jackson or something that you can run through an intercooler i would suggest turbo. roots type blower mounted directly to an intake manifold create a lot of heat and high iat kill power and motors over time depending on boost. also, increasing boost on a turbo is easier w/ a boost controller, vs. a s/c needs a different pully set to spin it more.

you will need to upgrade the fuel system and go kpro to do either properly. tuning is the key.