275/45-20 is the normal size most go with. Some tires vary from manufacturer to manufacturer. My Aturro AZ800's are the tallest and widest for that size 30.4 tall and 9.9 wide tread width. The stock RSA's are 30.1 tall and 8.6" wide.
You can go 295/45-20 in the rear.
Yes any bigger and kinda defects the purpose of 4.10s also... Not just mounting issues... Anything bigger would need to upgrade to 4.30s or 4.56s for good streetablilty... But that personal preference...