Avon tyres

Anyone had any experience of the Avon ZZ1's?

I need to make a final decision on tyres and thought I had decided on the Dunlop SP9000 then I found out Avon do the sizes I require:

275/40 ZR17 & 245/45 ZR17

Any help will be apprecieted asI have all but ripped my hair out over tyre choice!!

Paul,
I,ve recently fitted a pair to the fronts only and used them first for the Silverstone race on 15th March (fast corners),RAF Woodbridge sprint on 16th (demonstration straight line only), Snetterton practice day testing on 20th (fast corners) and this Saturday 12th, at Brands Hatch (tighter slower corners).
15in diameter and softer compound running at cold 18psi to 21.5psi after 15 laps at warm, dry Brands. Noticeably better turn in qualites there but understeering major downside at Silverstone probably due to higher profile flexing too much.I felt comfortable with them but would not trust them one bit in damp or wet race conditions but remember all cars set up very differently and for road use i would think great in the dry but quickly wearing.
I pulled race numbers off yesterday and went for rare road run into deepest Norfolk( Vanessa wanted her speed fix) and found them very stable upto around 140 er i mean 14mph officer, but tended to tramline badly on some surface conditions.
Hope this helps.
Regards,
GTA.