OP, a lot of people won't take you seriously because of your situation and lack of experience. I've been in your shoes though, so enjoy the great affordable car that the BRZ is and I agree with the parents, no need to get it all powered up as it will provide plenty of fun for you as-is.

As for your goal of improving looks, the simplest and most impactful visual way to set your car apart is to replace or paint the stock wheels. Pricing will vary from a few bucks for some plastidip to a few thousand for some lightweight alloys and new tires if you change the size.

Tinting your windows is another easy change for a couple hundred.

Aftermarket taillights, spoiler, and to an extent, exhaust are other mods that help in the looks department. The exhaust will also change sound and performance a bit, however.

If you have any desire to track the car, then forget the above and get driving lessons and tires, brakes down the road if you really get into it.

Once you decide to go performance, options will depend a lot on your own personal goals, but don't worry about that for now.

well of course, I have already bought all of the parts and have done what i can myself... I have already paid for the body work and its in the shop now, I'm looking ahead

I'd suggest an intake hose with a sound tube delete, and a good air filter. And if you have crickets, a couple ounces of ashless, marine two stroke oil per fill up will kill them after a month or so (that's what my experience has been, anyway).

get uel headers for that classic subaru sound then add ground effect kit and fake blow off valve for actual fast and furious lights and sounds.