If it's stock height, it will rub rarely and only when doing a fast tight turn or going up curbs while the wheel is steered left or right. If the wheels are straight even on high speed it won't rub. I have 20s on my lowered 360 and it's fine. Just a little mindful driving would do. The only way it won't rub up front when your on 20s is if you have stretched tire which is not recommended. It's like those slim tires you see from hondas or toyotas that have their wheel camber completely off. That's how they prevent them from rubbing even though their tire is so close to the fenders. If it's not lowered and you have 35 series back and 30 front tires your fine. Just little rub once in a blue moon which is not a biggie. I'll check the exact measurements on mine later when I come home but this gives you an idea what to expect.
Wow! 345, that is insane. The car barley has enough torque to break traction as is. Anyone else Please chime in what 20" tires you are running. PLEASE