I got my wife a 97 M3 its in overall great shape but the leather in it could have been taken care of a little better. The rear seats were stiff and VERY brittle, not to mention that I did notice this also in my buddys 2001 530. Im not sure whats up with BMW leather but it seems to be very pick and you have to take care of it or it will turn on you. Anyways, I got this stuff called Leatherique Rejuvenator oil, AND WOW this stuff made the seats like new in the wifes car and just made the seats in the mini soft. I have yet to try it out in the 530 but I figured you might want to try some if your seats are getting a little hard. I also use Auto Glym leather cleaner and condioner for qiuck jobs and my leather looks and feels like new in the Mini still.
I have been a leatherique user for years, it did wonders on my old E30 Convertible. I used their dye and full system on that car and everything turned out great. They also (atleast used to) give a discount to CCA Members
