I too run Yokohamas on the plus 8. They are around 6 years old now and I suspect they have gone hard cos things can get a bit hairy. Loads of tread on them and spare unused!
This is common to sticky semi track day tyres although they are fine in 'normal' use. You need to get them warm hence less grip in this cold damp weather.
I would have thought Contis were one of the best but perhaps you have the same ageing problem?
Sorry can't recommend anything, Vredestein seem good on 4/4's and
Toyo's on Aeros. Remember Art you were trying to keep up with smaller engined Aeros over the weekend!!!
I will follow this thread with interest....................




1969 4/4
1995 plus 8
1996 Plus 4 4seater
2002 Aero S1
2013 M3W
2014 Plus 8