Best Bang for the buck?

I am buying an 88 mr2 non turbo . It has an engine noise so i have to take the motor out. So my question is what is the best cheapest way to gain hp? I have owned one before and it was pretty slow. So bigger cams and trick head or stock motor with a turbo, or easy motor swap.
Any help would be greatly appreciated.
Thanks T

Intake & Exhaust
TRD Header
HKS Supercharger Pulley