I've done the route a few times now....always on a motorbike. As it's been heavily plugged by both Motorbike and car magazines in the last few months, I suspect that it's going to get spoilt!
I saw Countryfile last night and funnily ebpnough was watching Evo magazines Car of the Year 2015 video on YouTube yesterday which was also fumed on many parts of the route....some stunning photography as well as cars!