you can do a Weber carb, performance cam. TRD lev 2 is god, but idles like a v-8. full length header to 2.25" pipe all the way out. magnaflow straightthru muffler, aftermarket ignition system like an MSD, i have had my truck with, TRD Lv 2 cam. Bored out TB, Intake pipe, Supra AFM, MSD wires, ecore coil, 6a box, LCE header, LCE Cat, 2.25" pipe, and centerforce dual friction clutch. all of them were noticeable inporvements but still not enough forme all the money spent and it was still not fast enough, i would consider a engine swap if you want to really see a difference. how fast do you want to go? im shifting into 5th at 110, pushing it to redline.? back in the day i took out the supra afm and intake, those are in storage now i needed to pass smog.