Love your advise, i want to keep that stock headunit look on my dashboard. But i still wanna use good 6x5"s and 6x9's for goof sound and good bass. what would you recommend thats not costlyI used to build a lot of audio systems.
Most aftermarket speakers will claim to handle a lot of power, but for the most part, those numbers are pure marketing crap. The number that you're looking for is sensitivity. You want something from 87-91 dB at 1W/1m. Some speakers are measured at 2.83V, which is crap. For 4 ohm speakers, subtract 3 from the dB rating, but probably just avoid. Some speakers are measured at 0.5m, which is also crap. Subtract 6dB from it's sensitivity rating. For any manufacturers using these tactics, probably just avoid them. If they're willing to fudge their numbers that way, then what else are they fudging?
I prefer simpler systems over more complicated ones. 2 way is plenty good enough, 3 way or more starts to introduce crossover artifacts. If you can't hear them, I suppose that it's fine, but once you learn to identify them, they'll bug you. Just sayin'. Personally, I like to have as few crossover points and complications in the system as I can, while creating a good audio range.
Upgrade the head unit only if there are features that you want that the head unit won't provide. If you want MP3/WMA playback, bluetooth, or other input that the stock unit can't provide, then it's time to look for an upgrade. If you just want the CD/AM/FM that you already have, then there's little need. The actual sound quality improvement is minimal until you start to spend a LOT of money. Most stock decks are capable of excellent sound quality, provided that you use adequately efficient speakers (sensitivity from above.) If you go towards speakers which have a sensitivity of 90dB@1w/1m or better, then you should be able to approach permanent hearing damage with minimal distortion from the stock deck.
Don't expect miracles. I've built extreme SQ car audio systems, won a good number of IASCA competitions, and the sound is easily rivaled or beaten by a decent set of headphones and a portable CD player. A car is a really nasty environment for sound, and nothing can really change that. Small steps up for better sound can cost a small fortune. Be aware that the placebo effect is alive and well, and sometimes you can be convinced that you hear a difference (that nobody else will) because you spent more money. (Sound competition judges can "hear a difference" from exotic or expensive components as well.)
All that said, the stock speakers in my '99 Accord aren't bad. I upgraded the head unit, because the one it came with had a broken CD player, and I wanted to be able to connect my iPod, and have bluetooth capability, as well as CD/AM/FM. As it happens, I got DVD playing as well, but that wasn't really important to me. I'm still using the stock speakers, because they're in good shape, but I have some nice aftermarket ones that I'll probably install this summer.