I had the opportunity to top end run numerous BMW's and a few that come to mind now are , we had a M5 with a schnitzer pipe and tune, I got 270 on heads up display and it wouldn't go further! It was definitely limited, btw that was on a few occasions!
Then had a stock M5 and it ran into the 270 with the same zeal!
Like schalk burger running into a brick wall hehe
E92 M3 - two different cars on different occasions one touched 258 and the other 262 both on gps with speedo sitting at 270+
E93 335i speedo , get this 280 but according to OBC 264
E46 330iM speedo off clock and garmin 262

raise: on a downhill
E68 760i speedo 260 and true speed 250
E60 550i 256km on heads up
E60 545i 258km on gps
E36 328i 246 at redline in 5th
E46 330d 243 at most .2k revs from red line
*all tests were done on a pvt test track at my castle in the alps :fencelook: