NA engine ideas?

Ok i found a fairly decent 91 mr2 in my area for around 3500 its NA i reaserched it seems you all arent to fond on the turbo swap. So what would you suggest for upgrades someone make a supercharger? I'm not looking to make huge power just enough to where when i get used to it i can upgrade later.

turbo swap.

you will spend much much more on trying to make your NA faster.