Ok well you've done good so far and you're not in any "lost" section. If you really do intend to go turbo dont waste time with headers...look for turbos and other components. The exhaust will be ok but you would want a 2.5" or 2.75" exhaust for your turbo...I messed up royaly with that...I'm losing about 5-10 whp because I still have my 2.25" exhaust. Now if you just want to end the hassle and keep it N/A you can go find the headers, and get an ecu reflash and you'll be square.
As for right now. I suggest a couple things first while your deciding what you want because they will help you no matter your setup.
1. A big bore throttle body (BBTB for short)
2. Intake manifold spacer: to help reduce heat soak on those hot days. Hot air can really drop your power down just from that alone. Go to this link..he'll hook you up:
Hyundai Accent 1.6 DOHC Themral Intake Spacers $55 Shipped This Week
3. Get your intake manifold bored out...If you want I can sell you my spare. It's bored to match the shark racing BBTB (52.5mm).
All these will help you out now and later whether you stay N/A or go turbo.