Haynes doesn't cover the rear boot trim in the e46 Touring and most of the forum posts I came across about the matter talked about how hard it is to do and you shouldn't bother. However, most of these posters were happy to take their front door cards off to replace their speakers.
If you are reading this post then you are probably aware that the standard sound system in the e46 Touring leaves a lot to be desired and I was determined mine would have a sound system that was worthy of an otherwise great car.
I started by replacing the Head Unit, this was relatively straightforward. I fitted one with a rear USB input, the cable for which runs into the glove-box and is attached to 16GB USB stick with a very large number of albums on it. So I also removed the 6 disc multi-changer from the boot, I sold the Head Unit and Multi-changer over eBay and the combined price covered the majority of the price of the new stereo install! :)
However, the new head unit only showed up quite how terrible the original speakers are. There is plenty of information on the internet about doing the front speakers. I followed BSW's youtube video for removing the door cards and a separate DIY for the tweeter.
The sound was noticeably better, but was lacking bass so next I bought a small sub which wouldn't impede too much on boot space. I fitted this sub with a plug for easy removal. If I was going to do it again I may well do something like this: (especially since I have removed the multi-changer).
But I still wasn't happy with the sound. So I then tried to find out how to do the rear speakers and this is where things became problematic. Haynes doesn't cover the rear boot trim in the touring. No problem I thought, there is a wealth of information on enthusiast's forums about various jobs for the e46. But, unfortunately most people on said forums seem to think the rear speakers are too difficult and must involve some sort of black magic to get at.
Admittedly this put me off for a while, but I already had some speakers which I wanted to put in and eventually I bit the bullet. It was looking at the data sheet on realoem.com that gave me the confidence, since it showed that the offending panel is only held in place by a few screws.
http://www.realoem.com/bmw/showparts.do?model=AX52&mospid=47662&btnr=51_3949&hg=51&fg=65
Despite what the forums say I found this job to be fairly easy and straightforward, I certainly didn't think it was more difficult than a door card. And if you have any experience with removing trim panels you shouldn't either. Just take your time and think logically and methodically and it should be easy enough. It took me roughly two hours per speaker, but as always I reckon I could do it quicker now I know how to do it.
The following is a guide only and applies to a late model UK spec e46 with standard speakers, I can't help it if yours is different, but I doubt it is!
In my car the speakers were exactly the same as the front... which in my car meant I could fit 17cm component speakers with the relevant adaptor plates which you can get from eBay.
First things first, this is the panel we are ultimately aiming to remove (I will refer to this as the main speaker panel):
So, we start by removing the panel next to it which allows access to either the battery or the multi-changer (depending on which side you are working on). The first trim panel we want to remove is the one by the boot opening which has an interior light in it, it is held in place by two screws in these locations:
With the two screws out the panel is still held in place with two plastic clips (the same type that hold the door cards on). These clips are at the top where the panel meets the carpet, wiggle it a bit and then pull or pry it off and the panel should come off fairly easily. You will either need to unplug the light or pop the light assembly out of the panel (I found the plug very stiff and found it easier to just pop the assembly out). The next photo shows the panel removed and the clips I am referring to:
Next we want to remove the piece of air vent trim.
It is held in place by two more bolts, the first of which is just visible in the next picture (it also holds the main speaker trim panel in place).
Remove this nut now.
It is also held in place by a nut which is hidden under the piece of trim highlighted in the next picture.
To access it, we must first remove the two bolts that hold the roller blind clip in place:
Once we have done that and the roller blind clip is loose we can lever up the plastic trim which surrounds it, it is held in place only by plastic clips. It does not need to be removed, it only needs to raised up to allow access underneath it. Once you have raised it up, you will be able to remove the roller blind clip.
This is what you should see once you have done that:
In the highlighted area is a nut which secures the air vent trim, a piece of plastic trim which we are not going to fully remove and the main trim panel which we are trying to remove.
Undo that nut.
Now, you should be able to lift the top piece of plastic trim high enough to remove the air vent trim.
The air vent removed:
Once you have removed the air vent trim, you may as well free the top of the main speaker trim.
The next thing to remove is some sort of plastic rivet and they can be a complete pig. Of the four two of mine came out relatively easily, and two were absolute swines, in fact I broke the one in the following picture and had to replace it with a good old fashioned nut and bolt! The idea is that you remove the middle part of the clip and then the whole thing will come out, hopefully yours are not as stubborn as mine. If you have removed your engine undertray before then this is not the first time you have encountered these... except these ones have probably not been removed since your car left the factory!
Next you can remove the piece of plastic which surrounds the metal clamp for the rear seats. This should be fairly easy, the clips at the top of it are designed to come away first.
Next, you need to remove the two bolts behind the luggage strap clamp. These came out easily enough, but I had trouble lining them back up on one side... re-fit them sooner rather than later.
And finally, there is another of those annoying plastic pop rivet thingies at the bottom of the panel. Remove your boot floor and you should see it.
Once you have removed that the panel should be free... just remember that on one side there is a 12volt socket which needs to be unplugged before you can fully remove the panel! :)
And there it is the offending rear speaker:
Fit your new speakers and then refitting the panels is a reversal of the removal as they say.
Personally it makes a difference and I am now pretty happy with the overall sound of my system and it is a million miles from the tinny rubbish that used to be in the car.
