MysticMcF & rendered> If u guys are running 255 in the rear already the absolute maximum u could use would be 10mm.
Do u plan to slam your cars? If u do I'm pretty sure it would rub the rear bumper clip in the wheel well when the car goes into a big dip.
IMO 255 looks really nice and aggressive already.
Usually extended bolts come with spacers. They did when I bought mine.
As for where you could get them, I dunno. Sorry can't help u there.
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19" Axis Supermesh, Hartge Front, AC Schnitzer Rear, LED Rears, M3 Side Mirrors, M3 Trunk Lip Spoiler, Mrs. Chiu's Halos, Body Colour Front Bumper Reflectors, Clear front corner and side indicators + Solaris bulbs, M3 Front Strut Bar