yeah, piece together a turbo kit, even running low boost (6-7 psi) you should break 150 hp easily. you could do a used/junkyard setup for around 1000, or even a decent kit for 2500. i would never personally supercharge a car unless it was already making decent power N/A. its too much money and you dont see decent results out of a car thats only making 125 hp. you are paying over 2 grand, for less than 20 hp. and all the k20's ive seen were a bit more than 2000,

but to answer your question.....k20 or a supercharged d16.................go with the k20.

if you start wondering about the turbo....go to www.turbod16.com and download some of the videos there. a stock d16y8 with 9 psi... making like 186 whp, and 170 ft lbs of torque, and that would probably cost the same or less than the supercharger, and definetly less than the k20.