1M to csl.... Dangerous?

[Tinker]

Hello and thanks for advice.
I bought I stunning 1m last year. It's black with 9k miles every option and BMW performance seats and led steering wheel. But it sits in the heated garage not being driven.
I have recently bought a 55plate 60k mile e46 m3 which is completely standard and only 2 owners. Love driving this as I can drive it hard, park it anywhere and it is fun to drive.
I'm now debating whether to finally get a csl or not and sell the 1m and e46.
I spotted this one today. EK53 AFS.

http://www.autotrader.co.uk/classifi...?atmobcid=soc4

Full BMW service history with only one large gap on the servicing from late 08 to late 11 (but only 9k miles in this period)

8 previous owners. Does anyone know it and any thoughts on what I should do would be helpful.

Cheers