I dont know man that seams like a whole lot of work, and I wouldnt be using the D6's for my speakers b.c they are running my subs. Also this may seem like a noob thing to ask, which it probably is, but how do i know if an amp runs at 8ohms, or in the Boston Acoustics case 3ohms?
An active system is a tad more work but offers MORE flexibility in term of adjusting the speaker crossover points and levels to sound best in the given vehicle. Whether you go ACTIVE or PASSIVE, you will have to mount all of the drivers, run wire to all of the drivers, and you will have to tune all of the drivers so, ANY STEREO SYSTEM you install in a car will need some work to get to sound good. If you are not up for it yourself then maybe get a qualified installer to do it? Or by no means should you drop $800 on speakers if thing won't be set up and installed to the level of the drivers you are dealing with.
What amps do you plan to run?
As far as the Ohms question...IF YOU DON"T KNOW, ASK. That is the purpose of these forums...there are NO such things as noob questions.
All amps will run 8 Ohm loads...it just reduces the amount of power the speaker will see...In contrast a 2 Ohm load will increase the amount of power the speaker will see...But, then you have to look at the speakers efficiency...that changes everything in terms of the actual output.
An efficient 8 Ohm speaker can be just as loud as an inefficient 4 Ohm speaker on the same amp!
http://www.diymobileaudio.com/forum/showthread.php?t=31
Anyway, sounds like you may not be comfortable with running an active system?
If so, many of the passive system suggestions should work for you. Just try to listen to as many brands as you can to see what sound you like because more than any other part in the system, speakers tend to sound the most different from brand to brand.