As far as I know, all X3s are made by a subcontractor, Magna Steyr in their plant in Graz, Austria. So technically, BMW doesnt really assemble/make the X3.

Understandably, BMW does have its own plant in Thailand among other places such as South Africa. However, we don't get any Thailand-assembled BMWs in the US. The vast majority of BMWs coming to the US are assembled in any of their factories in Germany, with the X3 in Austria, and the X5/Z4 in Spartanburg, SC. A handful of South Africa 3-series may trickle in from time to time.