Dinan - D120-0585 - Front: 28mm - Rear: 19mm - Adjustable - F22/F23/F30/F32/F33/F36

Stock bar is 13 mm on the 328i/330i/335i/340i/435i/440i w M-Sport which means the new bar can be adjusted from 243% to 329% stiffer than the stock rear sway bar.