305 is more than enough to go 4.xx second 60-130.
I ve tested various tire sizes and 305 is ENOUGH.
All you need to do is set the COMPLETE VEHICLE AS PERFECT AS POSSIBLE SO THAT IT HOOKS.
I would not spend any money for widening the rear arches.
My sub 4.xx second 60-130 will be made with smaller than 305 tires as well.
sub 3 seconds 60-130 mph AWD M3X coming soon
4,23 s 60-130 mph E46 M3 TT
4,49 s 60-130 mph E36 M3 TT, 3,49 s coming soon RWD mode
8,45 s 60-130 mph 997 Turbo