Newbie questions

[maj]

Hi folks, Newbie here.

(Before I start, this question has probably be repeated on numerous occasions, so apologies in advance). I am currently in the market for a D3 3.0TDI Sport, looking to get suggestions as to what I should look out for it terms of common issues. I know that the Sunroof drains can have issues. Is there anything mechanical or electrical that I should definitely look out for.

I am looking to get a facelift model, preferably 2007 onwards, and really would like one with B&O system which I know are few and far between but I have seen a couple for sale in my price range. Being a more complicated system, are their any know issues with the B&O System I should be aware of?

Although I have already stated I am after a Sport model, what are the main differences between the Sport and an SE, other than the Sport sits lower and has a Sport steering wheel? My plan is to change the steering wheel in future regardless to a modern Audi wheel.

Does the 3.0TDi have a timing chain or belt? If its a belt then how often must it be changed?

I will also give the engine Terraclean before its remapped, would like to get a map to improve the economy. Has anyone had their remapped and what sort of bhp/mpg gains are there to be had?

Generally, how reliable are these cars?

Apologies again for the loads of questions, but having never owned an Audi previously I like to know what i'm buying into. I currently drive a BMW 530d e39 which I have owned for the last 7 years and is now approaching 200k miles. This car has never missed a beat and mostly just cost me on wear and tear items which i cant complain about. If it wasn't for the common rust areas and rest of the car slowly but surely starting to creak then i'm sure this mighty engine could happily do another 200k miles but alas all good thing must come to an end. Its been an awesome companion but would rather let it go before it starts costing me money. Plus the fact that my car being covered in rust does me no favours in my occupation as a Detailer in which i'm pretty good but my beemer doesn't reflect this lol.

Look forward to your replies

Thanks in advance

Maj