Choice of a diesel engine for 2010-2011 A5?

Hi,

I am planning to buy A5 right now and it's quite hard form me to choose the engine modification. I've always dreamed of A5 with 3.0 V6 engine and Quattro, but the people older than me say that I don't need that engine cause we don't have any places to use the potential of that beast, so they advise me to stay with 2.0 TDI, but I guess it's nowhere near the V6 when compared.
If I get a 2.0 TDI, I am buying it only with manual cause of the headache that multitronic gives, but what about 3.0 Quattro transmission, I've read that there's a tiptronic and an stronic, what's the difference between them?
Also, what are the biggest 3.0 tdi problems and to which places I should pay more attention when buying it to avoid buying a dead car?

Thanks for your answers in advance guys!