Wow.. Where to begin?? Speakers all come down to preference bud. Best suggestion as for that is goto Best Buy or Circuit City, listen to different stuff and see what you like best and what your budget allows.

As for the Infinity amp, yea its ok but you are just better off replacing it and getting an aftermarket headunit. If you want a really good sounding stereo one of the most important things is the headunit. A good headunit can make a difference, a great headunit can make a greater difference. The stock headunit will not be good enough to tune the equipment you are looking into putting in your car.

A Subwoofer is a viable option if you like bass. Just because its closed off doesnt mean you are not going to hear it. Since you dont want to go into competion stereo I would suggest a single 12" sub or 1 10" or 2 10" subs in a sealed box. The sealed box will give you good bass and clarity. This is more my personal prefference and I think I understand what you are looking for.

If you really want some help putting together a decent system let me know and I will help you as best as I can. I love helping people out with audio setups its an exciting project and can be lots of fun.

Hope this helps you out bud.

98' Eclipse GS- Hahn Stage 2- SOLD
02' Honda S2000- SOLD
04' Acura TL- Current Whip