All Eibach components are TUV approved, which means they have been properly tested and are made from quality materials, yes you will pay more but you will get what you pay for. Last thing you want is a when falling off.
I have seen some of the cheaper Chinese and American ( stuff from the USA is generally far eastern too) spacers fail due to loads and impact on a couple of the off road race cars I have worked on just due to poor quality materials, when you compare these to eibaches you can see and feel a difference. Just because they are anodised a fancy colour and have a fancy brand doesn't make them any good,