i have a 02 911 cab that i drive on the weekends as a pleasure vehicle, i don't track it or drive it hard. the car has the factory 18"wheels on it 8x10 on the back & 8x8 on the front. i want to replace them with gt turbo wheels but can not find 8x10's i am looking for. can i put 8 x8 on all 4 wheels & if so would there be a safety issue...

 

There is a reason Porsche puts wider wheels/tires on the back of the 911 - even the C4 version.
It's because with rear weight bias, the car will be less likely to go off the road backwards.

OTOH, if you drive the car like a Chevrolet Cruise, then it won't matter. But then why bother to own a 911?

 

Keep looking. They are out there. Search eBay. There is a reason Porsche uses the stagger wheel set.