I've got a nice set of Rays wheels on the car at the moment:
Smoked Chrome CE28N's (Front-17x7.5 ET+50, Rear-17x9.0 ET+63)

When I got these of Mike they came with Goodyear F1 GSD3 (Front-215/45ZR17, Rear-255/40ZR17) Although I think he had previously run 225 fronts.

Looks like the GSD3 are going out of production in these sizes and I've not been as happy as I was with the Goodyear Asymetrics.

I can't get the Asymetric or the Asymetric 2 in the 255 width for the rear, will a 245/40 be OK on a 9" wheel?

similar questions for the front although I can get a 225 Asymetric - should I go wider or stick with the oem width I have at the moment?

The car is about 30mm lower than standard and running a touch of extra neg camber.

obviously I don't want to order £500-600 on tyres and find they rub on anything or are too stretched.

 

The 9" wheel is only half an inch wider than oem so that's never going to cause any problems fitting 245 tyre.

They'll be a bit more stretched but I doubt you'll even see that.

 

looking very much like oem sizes and Goodyear Asymetric 2s all round for the next tyre change then.

 

Good choice.

 

Tyre widths do seem to vary from manufacturer, iirc the oem RE050 is slim fitting, where most are a bit wider in the same sizes.

I did find a website which gave all the dimensions somewhere...

Bit I'd probably be going for 215 and 255.