I am looking at upgrading to 18x11 wheels and 315/30-18 tires. The exact sizes are negotiable, but I'm wanting to be at or very close to those sizes. If I utilize the stock wheel hub placement (not looking into arm extensions or a wider rear end), what offset or backspacing is needed for these wheels? If I go with 0 offset, it looks like I'll have about 6" of backspacing, is that too much? Will that rub? Or do I need to look into negative offset wheels to get that backspacing number lower?