[Hale]

For performance, I'd say your best bet would be to start with a K&N Intake and mandrel bent exhaust. Both are rather restrictive on stock cars and be opening up them both you can not only get HP results both also gas milage (you'll get more air into the engine and thus using less gas).

Just know, you can have too much diameter in the exhaust and you'll lose lowend torque. I would say the safest bet is to have it increased 1/4" over stock and change the stock cat with a hi-flow cat. Also think about aftermarket headers and muffler as those can be restrictive from the factory as well.

And if you ever want to lift it, do what goinbig suggested, put on the lift first then find tires that feel in the gap. And if you want to lower it, have enough cash to do both at once because you'll need lower profile tires as soon as its lowered or else the stock ones will rub or might not even fit depending on how much you lower it.