New to the forum so hello

I currently run a 300bhp Impreza which im not looking to change just yet, but im pretty sure my next car is going to be an RS4. Unfortunatly though it will be an early one as this is all my budget will stretch to - a nice X, Y or 51 plate
I know running cost will be on par, if not more than the scoob, its major work i'd be worrying about. Is there any horror stories about engines/gearboxes/turbos etc on 60,000+ miles.
Would i be better getting a newer less mileage S4 with the V8 lump for the same price? or forget a car like this if id be constantly worried about a big repair bill
Cheers
Dan