yoko A048's here.
They seem to last longer than 888's before overheating, and there is an abundance of them second hand too. I recently picked up 6 part worn tyres for £96, and the set of 4 have lasted me 3 trackdays! fantastic value in second hand track tyres if you hunt them out.
888's are a brilliant tyre, but mention 'trackday tyre' in any pub in the land, and the man in the pub will name the 888, this gives it similar attributes to BMW M-parts, you pay a tax that isn't really justified.
I've run Federal RS-R's, 888's, A048's, and various road tyres, and I'm really liking the A048's at the moment, on my second set, with another part worn set ready for action as well.
If it's traillered, you don't need road legal, so it'd seem silly to pay £800 for a set of new road legal tyres.