My 98 HB takes 6.5" speakers all around, and that's what she's got. I went for Fusion FP-652s, and had only a slight problem due to Fusion speakers being generally a little too big for any application because of their massive magnets.
I've also got a Fusion Powerplant 12", w/ 1000W amp, and a Kenwood MP3 headunit. Poor little car runs first in class come the stereo competitions in spring. Last number I hit was 146dB with the single 12. Nothin beats Fusion for price/performance