A 2018 SQ5 for a 2016 plate RS6?. RS6 is a car i've had the itch to scratch for many years now & a garage local to me has the one i'm looking at for a good price & it's only done 21,000 miles. Decent spec & the performance model also. Only thing it's obviously been replaced by the new model which might hit prices of the older model even harder?. Thoughts please?.