Complex sentence: Tatra was making more of them, though, which became an issue in 1957 and 1958, especially since East Germany produced its own luxurious car, the Sachsenring P240.
Split into simpler sentences: Tatra was making more of them, though. This became an issue in 1957 and 1958, especially considering East Germany produced its own luxurious car, the Sachsenring P240.