Clear corners are one of the most basic modifications and is often the first modifications done to a car. Unlike some car manufactures BMW offers the European clear lights for sale in the US, they are an exact OEM replacement for the amber lights; however, they come at a cost.
Ordering OEM clears corners from Pacific or Circle BMW can lower the cost considerably but clear corners are still pricey. Recently aftermarket companies have started producing non-OEM clear corners at a reduced price. For a reduced price what do you get? I think a reduced product; the non-OEM clears did not fit properly in the front or rear.
In the front the passenger side needed lens had to be ground down with a Dremel tool considerable to make it fit, and the fit was still not perfect. In the rear the passenger side also did not fit having a different design from stock it also had to be modified with a Dremel tool. Further more the non-OEM clears did not come with bulb sockets, and the rears did not have the black plastic trim which comes with OEM clears. The OEM trim taken off the stock taillights had to be modified to fit on the non-OEM lights.
Overall it took several members of the performanceIX team an hour and a half to modify and install the clear corners. To be fair, once installed I do not think that most people could tell the difference between the two, even a trained BMW enthusiast probably could not tell until up close.
If you are willing to play around with the clears corners and do some modifications then the savings might be worth it. If you are going to have a shop install them for you or don't like to mess around get things to fit buy the OEMs. The time you spend making the non-OEM lights work will negate any money that you may have saved. It is a rare occasion that I say this but in this case OEM is better.