I have the OEM shades on my E90 M3 and my windows are tinted 35%. They only take about 10 sec to take out. I keep mine in all the time. My daughter doesn't complain about the sun in her eyes anymore and it doesn't interfere with my driving. I actually think they look better than the pull up ones that came in my X3.
'09 E90 M3 SG | VF620 SC | KW V3 | ARC Wheels w/AD08 | OnEighty Lights | BPM Sport coding | AA Catless Exhaust | BMW Performance Wheel | Recaro Child Seat
'13 X3 DSB with M Sport | H&R Springs | Gloss black grill | Coded by me