I'd say OP should just stick to non-mechanical mods right now and go read the through the Unabomber's Manifesto, attend a few local meets, drive and get familiar with the car.
Congrats on the car. You'll love it. For the "rumble sound" I suggest the SPT Exhaust if you can get it for around $900 or less. I have it on my 13 WRX Hatch and I love it. I don't really hear any drone from it, quiet when idle, and makes enough rumble to turn heads when you accelerate away.