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.
XM3 = all wheel drive E46 M3 launching
4,23 s 60-130 mph E46 M3 TT