If you consider how much money you'd spend porting the head, getting bigger valves and injectors, adding a cam, and maybe a larger TB to make your non-forced induction engine crank out a mere 30-75 HP more than it has...and compare that to simply adding some forged pistons with a mild overbore maybe and the computer/turbo that is going to give you anywhere from 50-150 more HP, I think the choice would be easy...you may want to still do the head mods and injectors also so you can bump up the boost though.
I've seen a few references to turbo-charging for less than $2,000...I've already spent $600 on the head alone just to give my carbed Ranger 10 more HP...