Actually single din units have more control, such as the alpine 9887 which you can go active with. As far as I know no double din right now can go active. But yes the more power and control you have the better.

yah, unless you have a pull-out screen it's going to be tuff looking at your rearview camera's video in those 1din 2.5" screens. :D

HAHAHA...I had the same problem after I came home with my Z! I went to the dealership a week later and told them to take a look at my rear speakers cuz they weren't working. They came back 10 minutes later and said" Your speakers aren't working becuz you dont have any!" Yea..I felt pretty stupid!

LOL ya I am actually glad they never had any to begin with.

Alpine 9887 Active (control)?
 

Please explain what you mean that the alpine 9887 "active control".

Not to make anyone sound stupid but active is for advanced users. Instead of letting a crossover or the amp set your crossover points. You set and control everything including the crossover hrz and all from the head unit. It allows for a lot more control over a system with a lot higher end components and amps. I personally was going to go active but never got to that point. But after about 2 days of running you can make a system sound amazing if it is installed and tuned right.

Alos the cool thing about alpines are if you do not want to do all that they have something called "imprint" which is a device which will setup your system almost as good as you could do by hand with a laptop and a mic.

In normal terms active means the most control over a car audio system.

This might help as well
http://www.caraudio.com/forum/showthread.php?t=146726

Alpine Active Control for Dummies
 

I did one in a Lexus suv a few months ago turned out well. I would say that the program the imprint uses is pretty simple and helps the acoustics quite a bit.

So does anyone know the size of the rear speakers for the people that "do" want to put speakers in the rear???? 3" maybe 4"

3.5 inches not nearly worth installing there.

I don't want to be the bad guy here but I have,IMHO, high end unit setup. However I do miss the fill of the rear speakers.

I bought 3" coAx and I should have them installed by the end of the month. Hopefully the addition of the rears will not ruin my current setup.

Btw if I am not mistaken I almost bought the alpine unit mentioned but if it is the same unit, you will need to buy "another" expensive unit to tweak the heAd unit.

I dont see what the big deal is if you have the money??? Why are people so quick to be negitive around these parts here partner : )
I would think it would be nice to have some surround sound in place...Guess thats a no-no for some reason other than money.

5.25"

I had rear speakers (JL) installed in base - 8 total in cockpit. I think it sounds great, and surround sound with DVDs is amazing. I'm tempted to sit in my car to watch movies but the wife wouldn't like that much (then again, maybe she would....)

Edit: My receipt said 5.25" but I checked the box - 3.5's were installed.

Focal does not make 3.5's so I wondering if 4" will fit! Has anyone done this?

I put Infinity 4" ones and they suck.