My 97' SC400. Rennaissance red w/ 110k miles (as of Aug 08') on Toyota's 1UZ-FE 4.0L 32-valve V8. I waited 3 years for the right model and color. These 1st gen SCs are quite hard to come by here in New England, and most of them are the early ones (92'-94'). IMO the 97'-00' SCs are the best looking cars. Nothing else has managed to appeal to me more than my SC.
Only mod so far is a cat-back exhaust system. This is a true dual 2.5" running completely split from the primary cats through to the rod millen magnaflow mufflers. Center cat and resonators have been deleted. I've also removed the spare tire. My best 0-60 run is about mid-6 seconds, and best 1/4 mile time was about 15 seconds flat, just a bit improved over the stock specs of 6.8 secs and 15.3 secs.
I originally got the exhaust done just for the muscle car sound, but it actually does help the engine breathe much better. Overall power doesn't feel like its improved much, except in the high end; however, it feels a lot easier to get the engine to rev. I'm already in the process of ordering a pair of SS headers, and other future plans include a high-stall TC and a new intake.
Aside from that, there's not much in the way of real power mods I can afford right now as a college student. I'm looking towards a long-term goal of either engine swapping to the 3UZ-FE or the new UR family, or just supercharging. I know most SC owners opt for the JZ engines for big power, but there's something about the sound of the V8 that just puts a smile on your face everytime you step on the pedal that a straight 6 just can't do.