I started doing mine today, after reading everything I could find on this forum!
..and promptly managed to break both of the stubs that accept the 2 screws on the bottom piece. The BMW dealership I bought it from offered to tidy up the the steering wheel when I bought it in 2011 and it looks like they already broke quite a few of the clips as well. Also painting over the original covering caused a poor surface to develop, admittedly after 7 years or so.
Everything else came apart quite well. I used plastic scrapers and my nails to remove the soft covering then used 800 grit to try and get a smooth surface - we shall see. Took most of the afternoon being slow and careful.
Currently everything has 3 coats of plastic primer which has acted as filler as I've gently sanded back after each coat . The backside of the bottom cover had the stubs superglued back in earlier and now I've used epoxy resin to try to strengthen them. I only have a few of the (very) stiff clips left so I'm in emergency mode!
I'm thinking as the stubs were very tight in the wheel after I had to pull them out of their slots, it might be worth a little lubrication, not just to get them back in without troubling the epoxy (as they were quite stiff coming out), but also when putting the torx back in- any thoughts?
I quite like the finish of the leather, it's always been treated and cleaned so I think I'm going to leave it as is.
Tomorrow will be more gentle sanding back to get the right texture and start applying the matt black paint. I wasn't going to apply a clear coat but after seeing the results on this thread I'm going to buy some tomorrow. Very Nice work!