Going to sound strage, but safety equipment. Don't skimp. Ever. 3" inch belts, decent helmet (I have a carbon Kevlar Sparco one, which I was wearing when I hit the tree head on. Due to the weights involved, if I'd been wearing a cheapy, it would have ripped my head of.....) Spend money on a decent cage. A nice driving seat (Velo, Sparco, Cobra...)
You drive a whole lot better when you know that your still going to go to work on Monday if something big happens.
To learn to drive a car, you don't need huge brakes. Make sure the one's you have are recently machined. Spend a bit more on a good set of pads.
Suspension. You don't need coilovers. Really. We did without them for years. Good quality shocks (Koni for bitumen, Bilstein for dirt) and a good set of springs. You can get them custom made for not that much at whatever height and poundage you want. Mix and match.
Swaybar: If you like, never played much with them personally.
Here's a biggy: Do one change at a time. That way you'l know if the change has been good, bad or indifferent. Change a whole bunch of things at the one time and the car turns to crap, your then working backwards to work out what you did wrong.
Don't worry too much about the power/ weight thing. Get the car ready, drive it, then start tinkering. I know too many people who have got anal with the car and you never see them because "the cars not right". Hell, one of my cars I've had for 19 years, and I don't think it's EVER been right! :P
Get a car, Get decent safety gear, get out there. Then start tinkering. Enjoy.