I have owned my 2008 3.0 TDI S Line for coming up a year now. (writing this info for if anyone ever has issues with water loss etc as I searched forum upon forum for help) This car has only now been put right. I bought it from an Audi Approved dealer with a warranty, turns out the warranty was the best thing I ever did. This car has had everything possible replaced since i've bought it, who ever had it before did a lot of messing around with it and the price for it was many of the parts have needed replaced. It has had a new turbo, new injectors, new DPF, Cat, EGR cooler, water pumps (where I learned it had a mechanical water pump and an electrical water pump - it's been an interesting year to say the least with this car) that's just a small list to get it to running perfectly. Some of it has been a joint effort to diagnose as it's had engineers stumped. It's been off to specialists. But we've got to the end and the last issue was it was losing a very small amount of water but it seemed to only be when I had been on a run and then parked the car up for some hours, it would use the expansion tank to just above the minimum. I was pretty sure at that point it was the tank allowing steam out through the neck/threads of cap but as I know there can be head issues without many of the usual symptoms I insisted on the engine being scope checked etc under warranty. All good and after the tank has been changed and i've changed the new cap to an A4/toureg cap the leak has completely stopped (we tried the caps before the new tank was put on) so it was definitely the tank warped but the new Q7 caps were wrong for the new tank. My Q7 has been in the garage more than at home which has been a nightmare but fingers crossed I can get what I want done to it now.

So on to what I'm wondering if people can help me with. My S Line has pretty much everything on it, but for some reason from what I can tell they didn't get the Bose or Bang & Oulsen systems so it's just the standard. I've got to get the door cards off etc but from the information i've gathered, because I can adjust the subwoofer sound/volume by the MMI this means I have the standard Audi sound set up. In my opinion, it's bad, but mines worse because my front doors, both sides are knackered, they work but the bass they output, is a crackle, screech, the rest of the speakers are good. I have the spare wheel set up in the boot where the original sub should have been installed if the upgrades were chosen and there is a tray next to it with straps, not sure what should be in that. I've combed the internet to find at least some pictures of the set up and this should have some type of amp or battery or something that looks like its connected to the sub, could be completely wrong. This tray is next to the compressor.

Questions:-

I've found a place that does front door speakers specifically for my Q7 and they've said I don't need a connector or anything and these will replace my originals without needing anything else messed with. Are they right that I can just replace these without having to do anything else? I know from what i've learned upgrading on these aren't usually just a plug and play thing but they are adamant these will work if just replacing them.

If I wanted to say retro upgrade to the Bose system they had or the other, would I need to have the MMI VCDS hook up or is there a way around this (I think I already know this answer but more than happy for someone to give me an amazing work around) and is the current wiring something that could be worked with for this or will it need adapted/new? In pictures I see a cable with yellow plug. I've had quick glance since getting the car all sorted but with the crap weather not been able to really have a decent look but can't see anything like this. Doesn't help not having much of a manual! Which moves me to my next question.

Does anyone know where I can get owners/wiring/audio setup manuals from that are better than the basics I have so I can see what/where everything is?

I've looked for all different threads and I know there are some similar it just doesn't fit with all the information i'm looking for so I hope this is ok!

Cheers!