Hi,
As far as mods go, for what you're considering don't bother. Dyno plots show that the standard air filter gives best results over all the rev range. Some may produce a better peak at one rpm, but not by much. For the cost of one, and the risk of it not filtering properly, it's not worth it.
I had a superchip (for a while). Didn't make the slightest bit of difference in my opinion. The engines in the auto are different to the manual. The torque curve is different, and suits the gearbox. A chip for a manual, may not be suitable for the auto anyway.
What do want to do with the car? Mod for looks or performance? If you are tracking the car, then upgrading the brake pads, and maybe stiffer anto roll bars will be a good start. Brakes are strong but they need cooling, so big air deflectors are great.
Just get make sure you get quality brake pads, don't be tempted by crap like EBC and the like.
If your fear of staying alive, outweighs the thrill of making the corner, brake.