I installed the same kit in my 97 850R. What I did was to attach the phone cradle to the hand brake lever using plastic tie down straps. It works great, much better than drilling holes in the dash.

Also I hid the speaker under the dash on the driver side. Just make sure you turn up the volume control on the speaker fully or it will be hard to hear.

Look here:

http://albums.photopoint.com/j/View?u=1169531&a=10636531&p=36356702

Are you sure you want to do that? The previous owner of my 850 had a cell phone installed to the right side of the dash. There are 8 horrid screw holes now showing their ugly faces to my passenger. The phone was screwed to the flat areas to the right of the stereo and ECC. I am sure that at the time the phone was nice, but since they get outdated every month, you may want to consider a less intrusive mounting method. Personally, I am going to replace the center console and the panel going from the stereo to left side of the glove box with a new one. Once done repairing the mess from the previous installation, I am making an aluminum mount that I can screw to the transmisson hump in the passenger side and then screw the phone kit to. This way, when the phone gets old, I can replace it without cosmetic damage to my car. Not to mention, look much more professional than a thing screwed to the dash. Good luck, and think hard about letting anyone put a screw into your dash.