Well, first off, if you don't want to change any internals, the turbo's out. To really get any decent amount of power off the turbo you'd have to drop your compression ratio down to 8:1, roughly. And to maximize the gain you'd be looking at changing your cams for a longer duration. Unless of course you wanted to put on a turbo off of, i dunno, lets say a weed eater that make like no boost to speak of.
Go with the wet 50 shot dude. Set up right, it should give you the kick in the pants you're looking for with out breaking to much, including you wallet.