S60 vs S80 Diesel

[mikeday1991]

Hello everyone,
New to these forums, so please bear with me!

I'm looking to part ex my old car and jump into the big Volvo team. Usual requirements, big car with comfy leathers, good diesel for all the miles and an auto/geartronic box!

I've narrowed it down to either an S60 or an S80.
I've read up more on the S60, so feel more confident on choosing one (2004-2005, Euro III, hopefully avoiding gearbox issues) but what about the S80?
Is the auto/geartronic box more sorted after a certain year? Anything else that makes the S80 worse than the S60? Do they change to Euro IV after 2005?

I'm swinging towards an S60, but want to keep my options open!

I'm looking to spend no more than £3k, but want to avoid as many nasty surprises as I can.
Do aftermarket warranties benefit these cars?

Thanks guys