Ok, I'll try to make this simpler.

Only your Clutch is worn. OEM spec clutch is just that, a direct replacement. The HD is a heavy duty clutch, which basically means it has a higher spring rate. The reason for the higher spring rate is higher friction. Think like dragging a empty box, as compared to dragging a box with 10kg worth of stuff in it. There's more friction force. The only reason you would want the HD is if you've modified your engine significantly (or tyres) to the point where the friction between your OEM clutch and flywheel isn't enough. But this isn't the case as you haven't done anything to your car yet. So going HD clutch will only mean a heavier clutch pedal but no difference in real world performance.

With the flywheel. Your OEM one is fine, you don't need to change it. A lighter flywheel allows your engine to rev faster when there is no load on it. Basically means when your changing gear or in neutral, the lighter flywheel will make your car rev faster, making it feel much more responsive. It'll also loose revs faster as well, meaning if you change gears slowly, you'll miss the matching revs. A lighten flywheel will not make your engine produce more power, nor will you accelerate any faster. The reason manufacturers have weighted flywheels in the first place is for 2 reason. 1. So make the engine more livable. What I mean by this is that when you change gears, the revs drop slowly instead of dropping to 1k rpm in an instant and thus requiring you to heal toe to drive smoothly. 2. It smooths out the power pulses in each revolution using it's weight as momentum. A 4 cylinder only fires twice per rev, and without the flywheel, that would feel lumpy as.

My recommendation would be to just grab an OEM Clutch and be done with it. The OEM can handle slight increases in power as well, so if your getting CAI + Headers + ECU, and that's about it, it's more than enough. If you were going to add super sticky tyres (245+ extreme performance) on top of those mods and go racing (full throttle off the line etc) then I would grab a HD or even a racing clutch as they use ceramic which is a lot tougher.

Oh, and installation will cost you more than the clutch itself. Just a warning. If you are going to grab a flywheel, it's cheaper to get the flywheel done with the clutch together as taking the thing apart is a bitch (although putting it back in is a lot worse).