Cleaning up after my predecessor

Hello all,
Quick intro: I'm Indian, and have only driven foreign cars up to this point.

That being said, I enjoy working with cars, and have several friends that enjoy working with cars. I thought the 97 Riv I bought would just be a basic fixer-upper, but as I'm delving deeper into the inner workings of the car, I'm finding the remnants of jury-rigging gone wrong.

I have three things that I want out of this car, and all are out of my field of knowledge.

1) Make fun car go fast

2) Make fun car sound good

3) Make fun car look good

Both are challenging, not because of time constraints or money, but because of the morons who owned the car before me.

I don't know what kind of responses I'll get, but what should I focus on first? The car runs "fine" now at 165K, but I have no indication of how long that will last.

The previous owners (I don't know which ones) seem to have taken off the driver side door panel multiple times. So the inner paneling on the driver side is falling apart.

They also appear to have installed their own sound system in the car, as can be noted by the 1000 watt amp and the two 12 inch bass speakers in the trunk. The downside is that it is pretty obvious that there was no thought about the wiring, as leads are randomly hanging out of the door and the trunk.

I've replaced the tires and the shocks, and I have a friend who is itching to get at the supercharger. The hub caps that I assume came with the car are long gone.

The final fun times is that the AC stopped working before I bought the car, as well as the fuel gauge.

So at the end of this ramble, what should I go for first?

I'd do anything that the engine needs first. I'm right at 165K with my car too and the engine is probably the "worst" for lack of a better term. Check your LIM gasket and anything else you might suspect, if you have any. I'd also check the pullies and both belts. It doesn't hurt not to and It's easy to do. Also look at all your vacuum lines.

I'm coming up on two years with a 97 that had 200k. I started with a power cleaning under the hood followed by in and out on rest of car. Changed plugs, wires, belts, one fuel line, fuel filter and various bulbs. New brakes and tires. Replaced transmission pan gasket and rack and pinion.

Oil pan gasket is making me nuts but can't make time to change it.