Update:
Turns out I ordered the wrong unit. Here's the full rundown:
On Friday (New Year's Eve), I called Enfig Car Stereo of Carlstadt, New Jersey in hopes of buying the Dension GW33BM4 unit. Turns out, they were closed, so I carried on. Sunday, I did some final research before buying the unit, and checked Dension's website for compatibility. They recommended the Dension GW33BM1 for my car, which has a Business CD head unit, so I looked around for who had it cheaper, and finally settled on a vendor (powerseller on eBay). Today (Monday), I received a call from Enfig. I didn't expect a call from them last week as it was New Year's Eve. The person on the phone pretty much was saying he didn't stock it as not many people buy it, but he could have it by the end of the week. Unfortunately I already ordered and I told him this. Next he offered to install it for me for free for the sole purpose of using my car as the base for the creation of an instructional installation video. He had tons of videos for other makes, but none for BMW, especially a 3 series.
I'm impressed by the fact that they even offered to do it considering I didn't buy it from them. So, we talked for a while and found out that I actually ordered the wrong one. He was telling me that the BM1 was actually compatible with only the older E46's that used a different connector. So, he ordered up the correct one for me (BM4) and said he could have it this week.
He seemed very knowledgeable, and I am very pleased with the customer service. They do have a website (www.enfigcarstereo.com) so you don't have to go to the store to pick it up if you don't want to or are too far away, and I highly recommend them. I even have experienced their ordering side, as I ordered the cable (IPO5DC9) from them and they had it in the mail the next morning, tracking number and everything.
So, I'm not sure if I'm going to really have a writeup on this as it would be redundant; he is making a video of the install with my car. If he finishes it/when he finishes it, I will post a link to it here (or in a separate thread). I'll make an attempt to document the install with my own camera as well, as I'll be there when the install takes place, so I'll post that and will post the link to the video at a later date.