Well I have been absent from the forum now for about a year focusing mainly on getting my degree. Consequently I have been driving around with maybe the worst sounding setup i have ever had. Way too many highs, and its missing alot of vocal range and the obvious low end rumble that i have come to appreciate from systems i had before. Then the front mid-ranges started to cut in and out on me with the tweeter still playing and it became unbearable so I decided to take on a little upgrade.
I am still a college student on a tight budget so Equipment is going to come in as i can afford it and thus far this is all that i can afford, lol!
Full System Plan:
(2) Arc Audio ACS Tweeters some may know it as the Rainbow CAL25
(2) JBL GT4203 4" Component Mid-Ranges in the Stock Locations
(2) JBL GTO1514 Subwoofers in Infinite Baffle
(1) JBL PX300.4 Powering Underseats and Component Midranges
(1) JBL BPX500.1 on Subwoofer Duty
(2) Factory 8" Underseat Midbasses
(1) Audison BitTen Processing Everything
What I Have Presently:
(2) Arc Audio ACS Tweeters some may know it as the Rainbow CAL25
(2) JBL GT4203 4" Component Mid-Ranges in the Stock Locations
(1) JBL PX300.4 Powering Underseats and Component Midranges
(1) JBL BPX500.1 on Subwoofer Duty
(2) Factory 8" Underseat Midbasses
Why i decided on an infinite baffle setup?
A few things came into mind. Firstly: I pretty much know that this setup is not going to be as loud as what i had before or anywhere near it for that matter. Secondly: I've always wanted to do it. Thirdly: This car is so well sealed from the trunk area that it basically is almost 100% ready for such an install. Last but not least: This car is RWD and has about 240hp with the little mods that i have done to her. I like to get her sideways in the rain, and the last thing i need is a box flying around in the trunk, plus the limited amount of trunk space that i am losing is like a godsend.

"late nights, rain, parking lots, and a BMW" recipe for drifts!
I am not set on this 100% but i plan on using the Audison BitTen as it allows me to take the signals directly from the factory amp in the rear of the car and automatically de-equalize it to a flat response combining the factory equalized and crossed over front mid-ranges, mid-bass, and tweeters. From there i can set my own crossover points for the new equipment and in the process keep the factory Bluetooth, stock appearing interior, and Satellite radio and so on.
I decided on these Mid-Ranges as they were first relatively inexpensive, and they fit the required mounting depth i needed of 50mm or ~<2". Plus, they were so cheap that if they do not work out the money i spent on them would not really bother me that much.
Anyways All i have come to do so far was install the Components up front so here are some of those pics.
Christmas on the Dining Table:

GT42 Midbass:

CAL25 Tweeters:

********German Tweets for a German Car
Replacing Stock Tweeter:

********These tweeters just dropped right in without an issue

********Weatherproofing Foam Even Went back in without an issue!
Installing The Mid-Ranges:
This proved to be alot more difficult than installing the tweeters as the factory midranges are mounted directly to the door card and have a different bolt pattern than any other speaker out there. Nothing I couldn't handle, but something that was a little more involved than the tweeters.
To install them i ripped the original speaker cone and suspension off of the original speaker, I then used a dremel with a rotary bit and cut away the structure of the midrange from the original suspension landing. This left me with a ring basically that was able to bolt directly to the door card but the a 4" cutout in the middle just large enough for the JBL midwoofer to shimmy into place without a single gap sealing against the back of the door card on the edge where the JBL suspension meets its landing. Enough Talk Here are the pics.

Do not attempt any work on a BMW unless you own a significantly sized collection of these!

Removed 4 screws on the passenger side, and 3 on the driver side all positioned behind the wood trim on the driver door, with the addition of one behind the "oh sh!t" handle on the passenger door.

Here is the mounting ring cut out from the original speaker. I tried to retain the factory plug so that i did not have to cut any of the factory wires in the door but that created an issue with the speaker fitting into the trim ring, it was that tight of a fit. Which is always good.

So i had to do a little wiring, which is just temporary until i get the passives for the CAL 25 on the next trip that my dad is making. Here you see the factory wire coming into the door blue/white and blue/black tied together with the tweeter wire and inline passive green/black, green/white then but connected to the mid-range grey/white grey/black. The mid has an inline lowpass built onto the speaker itself. When i get the ACS passives all the current passives i have on now will come off but for now they stay on.

Here you can see the mid-range bolted into the door card as well as the built on crossover for the mid. I used the quick disconnect connectors instead of soldering the wire directly onto the speaker because i had a window regulator fail on me and if it can happen to one door it can happen to another and i would like to still be able to remove the door card if that occasion arose.
Bolted door panel back on after installing it all and stuck the JBL Insignia on the speaker grill using some butyl tape!

That's all i got now........kinda! The amps are already installed in a different configuration, and i have an additional 2kwrms powering a 12 that i dont plan on using but it fills the low end temporarily.