http://www.dunlop-tires.com/dunlop_uk/I ... =passenger
Wet handling is "lower" on the GT versus the "normal" .. not sure if that makes a difference to your choice, not sure the scale of the pretty curves or what they really mean

Digging around on the web the R01 and J are Vehicle manufacturer specific markings which Quote "indicate that a tyre has been fine tuned to meet the specific performance needs of a particular vehicle or range of vehicles It is important to ensure any new tyres you fit have the same markings."
RO1 is Audi (specific Audi Quattro models)
J is Jaguar
FWIW
AO is also Audi
* is BMW
MO/MB/A-MOE/MO1 is Mercedes
PE and NO/N1/N2/N3/N4/N5/N6 is Porsche
VO is VW Tourag