I know this is your first post so I'll go easy on you but this should really be in either the Protege5 or Performance forums.
As for more power, the most commonly taken route for N/A cars is to go with a new Intake/Header/Exhaust. There is also the more risky option of going with Nitrous Oxide but be warned that you should really know what you are doing with that.
For even more power, you can go with a custom turbo as some members here have done(check the Forced Induction forum for more info), but be warned that going that route is quite costly and requires even more knowledge(or a great mechanic at the least).
As for the tires....I guess I'm not knowledgable here, but I don't quite get how changing the tires as long as they are a proper fit for your car in terms of diameter etc will drastically effect the gas mileage or the power(unless you mean just the amount the tire grips off the line etc)...help me out here people.
White rims on a white car would look nice I think, but ultimately it's a personal opinion thing so go with what you like.