Which Stretch tyres on Audi B7 Help

[tdipower00]

Hey Guys,

I was wondering if anyone could shed some light on the topic.
I have an Audi Avant B7 lowered on a coilover kit currently with Audi 18inch S-Line alloys (RS4 style)

I have a set of Porsche Split Rims
Fronts 9Jx18
Rear 10jx18
Both offset et57

My question is what size tyres shall I go for? Been told to go 215/40/18 and 225/40/18 on the rear. Will this be too much stretch? Will I have to lower the car more? At the moment with the S Line alloys they are just under the arches)
I've heard a few horror stories with to much stretch...not holding air and as there is no give on the tyre walls when taking a corner the tyre slipping off and destroying the alloys!!!

So whats the best size tyre to get that will look cool and be safe?
Pictures would be nice..

Thanks in advance guys
Rich

[Buck6687]

those sizes sound about right
use this site to get an idea of what sizes look like together: http://tyrestretch.com/
for example heres my 205.40.17 on a 10j, which is on my e36, its one hell of a stretch but i have no problems with loosing air or unseating round corners(trust me i have tried and its been fine for drifting)

[tdipower00]

cool thanks buddy