I've had rolled fenders on three cars. Never cracked any paint. The key is to heat the metal and paint before rolling. Works flawlessly every time.
'02 ///M5 Imola Red / Imola Red '09 335i Alpine White / Coral Red
'04 E55 AMG Brilliant Silver / Anthracite
'96 318i Alpine White / Black
'01 330Ci Titanium Silver / Coral Red
'96 328i Jet Black / Black