Taken from another forum...
LE89000 was the first Z4 M roadster built, on 11/29/2004. LE89999 was built on 4/25/2006. So they built 1000 LE M roadsters during that period, from November 2004 to April 2006. Very few cars were made until February 2006, when volume production began. So almost all of the LE cars
were made between February and April 2006. At that point they switched to LY cars, starting with LY52000 on 4/26/2006. The remainder of the M roadsters were LY cars, ending with LY54041 on August 16, 2008. And then that was the end of the road for the US built Z4.
LE89000 was the first Z4 M roadster built, on 11/29/2004. LE89999 was built on 4/25/2006. So they built 1000 LE M roadsters during that period, from November 2004 to April 2006. Very few cars were made until February 2006, when volume production began. So almost all of the LE cars
were made between February and April 2006. At that point they switched to LY cars, starting with LY52000 on 4/26/2006. The remainder of the M roadsters were LY cars, ending with LY54041 on August 16, 2008. And then that was the end of the road for the US built Z4.