I had these on my E90 M3 for 3 years, and did a number of track days with them. No issues. They aren't the lightest, but I didn't have any problems.
__________________
Current: '18 AW Performance Edition m240i
Gone: '15 Mineral Grey m235i || '07 Silver Grey M Coupe || '11 Space Grey 328i XDrive || '08 SparkG M3 || '01 LSB M3 || '01 TiAg 330ci
|