Tokico is not a the same quality. Like above I have never heard of the on BMW's. But my on experiance with them went like this.
A friend of my dads (he has placed in top 3 in SCCA nationals, great driver) drove a 93 MR2 turbo. He put new tokico struts on it when he bought the car and was an avid auto-x'er. He blew the tokico struts in his car 2 times during 1 auto-x season. After that season, he switched to Koni adjustables. He ran 2 seasons with those, before he sold the car. Still with strong struts. Bilstiens are supposed to last longer than Koni's... I would recommend not getting tokico. However, he was satisfied with the handling of the car. Hence why he bought another set to replace the blown ones thinking he got a bad set. However, he was much more satisfied with the Koni struts.