Guys, I don't think there's value to upgrading the rear to 6.0 vs. keeping 5.25 all around, as lotus_dp observed the rears are just fill. They don't sound decent enough to be anything else unless you put some serious engineering effort into it.
If you want "decent" quality sound, go for the 5.25" speakers in the front that you like (head to your local car audio dealer and listen as each person's ear is different). Then for the rears, personally speaking I went with Kicker CVT 6.5" subwoofers and a 800 watt amp right behind the passenger seat. For an "Open" air design, these subs do well, however making some speaker boxes for them behind the rear bulk head will result in the best overall sound quality.
The great thing is, you lose no packing space, and the car still "looks" factory. If you choose to go this way, let me know and I will send you the "details" to make it fit nicely.
My PO did the same - except used the baby JL subs in the rear holes. I only use it at red lights. Tough to get a whole song in. My JL fronts also have discrete surface mounted tweeters, but they are a bit harsh..Is it a bad sign if you have to throw a towel over your tweeters to prevent you from getting a headache? I think it is.
I understand what giant is saying but I do think the rear needs some midrange fill, not just bass. My vote is to put in whatever 5.25" you want, unless you're willing to go high end and install tweeters in places no man has gone before, etc. C2s if it makes you happy. Buy one of the small modular subs to slide in behind the driver seat, and an amp like the Genesis unit to go behind the passenger seat. No loss of space, stock look.
Thanks guys. My goal is to make the vehicle more livable, so I figure any speakers will be better than the two holes back there now. In addition to missing the speakers, the vehicle seems to be missing the mounting plates that are required with the harness bar. These are items #2 and #3 on the following diagram. Any idea were I get these other than a Lotus dealer? Will using these inserts require a shallow-depth speaker?
Zinhead, I don't think you need a shallow depth speaker, but mark my words because I've done it, you can spend almost a grand on top of the line 6.5" separates and it will barely sound any better unless serious audio engineering (e.g. ideally locating tweeters) goes into it.
Edit: I've never seen those inserts before. They may make a little bit of difference.
I did car audio for 12 years. So all I can tell you is bring your own music, pick you speaker size and play your music. Close your eyes and listen as they flip through the different speakers. Buy the ones that sound good to you.
They might be cheap, they might be $$$, but those will have the tone that your ears prefer.
Each company has their own "sound" and it also varies in the companies speaker size
Follow this simple test and you will always be happy with your choice
IMHO, upgrading the sound in the car is pointless unless you include a sub.
As for the iPod wire, it will depend on your head unit. My car for example came with an iPod connector (which I removed) that plugs into the back in the AI-NET socket. Assuming your head unit supports this or alternately a line-in jack, you can pull the head unit fairly easily, install the wire, then fish it through the dash behind the airbag with some fiddling (and without disassembling the dash). Bring the wire throught he passenger-side cubby and run it under/through the divider onto the aluminum shelf over the passenger/s knees (this is where the factory iPod wire would normally run.)
Any tips or instructions on how to slide out the stock headunit? It has an ipod input listed on the face so I'm assuming its got an input in the rear. I would tell you exactly which headunit it is but the car is at home and I'm at my parents this weekend.
You need head unit removal tools or a pair of thin knives which slide in on either side of the head unit (remove the bezel first). That will disengage the latches and you can pull the head unit right out.