PART TWO: COMPLETE DIY PROCESS-
It took me about 12 to 15 hours of actual DIY prep and installation time.
This was before the month-long wait to get all the parts in the car and working (a fully working replacement monitor took a bulk of that time to come in as I literally went thru 3 bad ones before I finally got a brand new working monitor).
The tools required are your basic ratchet kit with 8mm and 10mm being the most used heads. Also a good torx set with T20, T25, T27 and T30 as well as the T50(for the rear seat belts) drivers being mainly used. Electric pliers, a clean dull butter knife or pry tool and a small flat head screw driver were also essential in the retrofit. Also have a scissors, lots of zip ties and electrical tape nearby. Said and done, surprisingly, there are no special tools or any textbook knowledge of using tools required for this DIY.
Knowing what I know now I can DIY this again in about 3-5 hours. Most of the original DIY time is spent figuring out stuff. Like removing the front seat took me less than 5 minutes and the rear seat took even less time but I spent about 1 full hour maybe more figuring out how to remove the two rear seat head rests!
The DIY instructions I was following only said that the head rests each pull right up but didn't mention on some E46 cars they are held in place by stubborn, tiny and impossible to see U clips under the rear deck. It took me about 40 minutes to find this out on my own and another 20 to 30 minutes figuring out how to get the U clips unconnected.
The thing you realize with this DIY, like most DIYs, is that it is really easy to complete once you know what it is you are doing. It is just the little unexpected things you come across that can really stump you (like the rear head rests in my case), but the big scary things you expect to spend all day on is really easy and takes about 5 minutes to remove or install (the front seat in my case).
Here are some pictures from the grueling experience (in the end it was worth it...sort of)
Going into this DIY be sure to keep a side-budget of around $100 to $600 for unexpected stuff. The clips on both my C P!llars were old and brittle and broke clean off leaving me to purchase two new replacements from bavarianbmwparts on eBay for about $30 each. I also broke the child seat anchor covers on the rear deck and to my surprise it is a discontinued part at all the USA BMW Dealerships and can only be special ordered thru the Canadian Dealership from Australia. Three weeks shipping and they cost $10 each. I also broke clips on my door sills and B P!llar during the DIY but don't need to replace those since they still anchor into place. But just to show you that you need to expect trim and parts to be brittle with age and to break when you remove them.
Laying the cable was easy I started at the rear seat and attached the rear deck/mid car connectors first: the BM53 antenna, the ground, the Mk4 GPS antenna (the seller who ripped me off with the monitor must have also forgot to pack the antenna so I ended up buying a new one on eBay for about $10). In fact removal of the rear deck was the hardest-to-figure-out part of the DIY.
The front driver seat was easy to remove and I didn't have to take the seat out of the car. I only tilted it out of the way to access the carpet below. And the carpet is already pre-cut and peels back easily. I ran the harness under the sills to the carpet entry point at the base of the B P!llar going under the driver's seat to the center console. Maneuvering the hefty 17pin front end connector head under the carpet up to the console/tranny area was tricky but not difficult. This took about 20 to 30 minutes to do. On the sedan I think it is easier to do than the coupe because I found that I didn't need to cut or make a slit in the carpet at all. Also on the sedan you do not have to remove the front driver seat belt on the B P!llar. There was no real surprises here but it is important to keep your work neat and organize or you can easily lose track of what you are doing.
Even after I got the main two trunk brackets there was still extra mounting brackets, about 20 bolts and body nuts that I needed to get everything mounted properly. Everything is in metric it was hard to track down the correct bolts (here in the USA) and I eventually went to the BMW dealership where nuts and bolts are $1.75 each. In this picture I used a Folgers Coffee container to support the BM53 and the Sirius is taped up and tucked in the back behind the car's frame. I need to get the BM53 bracket and the bracket retaining bolt ($24 at the dealership), a Sirius Receiver bracket kit and the oddment tray that replaces the CD Changer above the MK4 (about $14 at the dealership):
Said and done when all the parts are properly mounted: My car already had a Navigation-ready Sirus Receiver that I also mounted in addition to the BM53, the original HK amp, the MK4, the Alpine KCA-420i iPod adapter, and the Oddments Tray that takes the place of the CD Changer above the MK4 drive.
Also the new trunk wall lining mat trim and tray are needed. I bought the Tray for $30 at the BMW dealership which was the only place I could find it and the Trunk Mat Wall with the CD Changer/Navigation-Door from bavarianbmwparts on eBay for $40:
The drama that ensued at the front. The connections can get messy so it is BEST to work in sections. Finish at the back of the car first before tackling the front. They are more connections at the front of the car that need your undivided attention and care when making them. It only looks scary but it is not and literally should take even the most clumsiest DIYer about an hour to connect everything, replace the HVAC/ashtray and push in the new Monitor. Make sure the battery is still unplugged when you make your connections or you will run into problems (don't me ask how I know).