Audio upgrades in 2004 non s-type

Hi all,

I just got a new 2004 RSX recently (not the S-type), and want to upgrade the audio components asap. I already own an Apline 9813 mp3/cd HU which I plan to install. From what little info I can find online, it looks like the non-bose system only requires a simple wire harness and adapter kit. right? The Din opening looks fairly standard, but I was curious if there were any clearance or depth limitiations.

Also, I will probably upgrade the speakers. Crutchfield shows a short list of 6.5's for both front and back, but lists them as "P" install (meaning adapter bracket required). If I don't buy from them, where can I get the correct adapter?

Any recommendations for good 6.5's for under $150/pr that have enough bass response to avoid having to install a sub (I'm not THAT into monster sound and won't be cranking it...just want something that sounds clean with decent range).

Finally, what about those little component speakers on the dash? Will using a wiring harness simply bypass those? Or do they use some kind of factory installed crossover that I have to bypass? If this is the case, I may just opt for new rear speakers.

Thanks in advance for any info! btw....LOVE the CAR!!!

Mitch