Roadster owner's this is by far the best product to use for the rear plastic window, this is what was made for them by bmw
I have tried the mequires 2 step and this is by far easier and better then it is
simply rub it on and rub it off, that is it, 1 step and no mess
Note: I have not gotten it on the fabric so I do not know of any affects to it, but it was made for the bmw rear window by bmw so I assume there is no problem
PART #81229407665 $ 8.50 approx.