im looking to get a set of wheels and tires what size can i get away with/what would be my limit without damage

My question is can you go wider on the same GT wheels, such as 255/45/19?

Yeah I'm wanting to put 20x9, 20x10 staggered fitment on my G8 GT but I don't know what offset I should get. HELP ME!

Yeah I'm wanting to put 20x9, 20x10 staggered fitment on my G8 GT but I don't know what offset I should get. HELP ME!

I'm running 20x8.5 up front and 20x10 in the rear with a 45mm offset. If you lower it youre gonna rub. To fix the rubbing you need to either get a larger offset which may be hard to find or trim or roll your inner rear fenders. I chose to trim mine so I wouldnt have paint damage that may occur if you choose to roll them instead.

http://i440.photobucket.com/albums/qq125/incon3037r/GT%20lowered/G8lowered005.jpg
http://i440.photobucket.com/albums/qq125/incon3037r/GT%20lowered/G8lowered008.jpg
http://i440.photobucket.com/albums/qq125/incon3037r/GT%20lowered/G8lowered009.jpg
http://i440.photobucket.com/albums/qq125/incon3037r/GT%20lowered/G8lowered017.jpg

incon,
What size tire are you running? I too want to run either 20's or 18's by 10's but I want to run a 305/35. I want that BMW M3 or M5 look with the wide tires in the back and normal size up front. I alway like to run a bigger size tire then the actual rim or wheel, reason being not only the look but incase you hit a curb for some crazy reason. So your offset is 45mm and you had to cut the inner fender to clear the tire?

what size rubber are you runnin in the rear