It's good that you have realistic goals for what you want out of your car. Street oriented performance is an obtainable goal. IMO that means reliability, which is what I would aim for.
Do you have a price range and budget in mind? If you don't yet, then set a budget and try to stick to it =)
I would do modifications that you can build upon. An example of this would be some sort of engine control (EMS). This would allow you to get the most out of any future mods.
With that being said, an intake and exhaust are also good mods to build on, and will probably give you more gratification (you can hear and see them!) The stock EFI system is hampered and cluttered by a restrictive air box, AFM, and small throttle body. IMO one of the best ways to clean/clear up that problem is with......... you guessed it, aftermarket EMS!