As far as gears go I've had 2.73s which are an abomination to any car, swapped those for 3.73s which were much better, if your going to do more town than freeway driving, than get the steeper gears but I personally wouldn't go lower than 3.55s.
As for recaros get them, and again, get them. And I'll put it this way, from the factory the seats are a $1,500 option to buy them aftermarket they are 3 grand for the 13 and 14 mustangs. The recaros will be better than the stock seats granted you aren't really big or have back issues and so forth. As an added plus if you don't like them there will always be someone who will be willing to swap you seats and probably give you cash on top.
As for the whole parents buying the car for you it's whatever man just don't be the stereotype. I had an 16 year old coworker who's parents bought him an 07 Shelby GT500, he wrecked it. There was another 18 year old kid who's dad bought him a brand new Audi R8 V10. He ran a $160,000 supercar through our automated car wash frequently, well that was until he rear ended someone doing a 100mph on 40mph street. Rule number 1, don't be dumb and enjoy and baby that thing. Sent from AutoGuide.com Free App