I had a chat with my buddy on the phone and he said there is a reason behind the poor quality of this series. Kyosho moved the factories to another location in Mainland China to cut cost. The factories have never produced any Kyosho diecast models before and British Car 2 is the first series the workers assemble in production lines. The QC workers are not very well-trained; they could not identify the defective cars and take them out. Therefore, we see so many damaged cars being sold in ebay.
He speculated the quality of the diecast models will remain terrible for at least one year and warned me to make small order for future releases.
I guess I will not import too many box sets of BMW Series 2.