Trouble is, the M version is only available in certain colors. If you want a black 635 or green or bronzeit or the other colors not M colors, you will not have a choice. I wanted black, so the hell with the M. But if I want to add a red one, then it might be the M, but it might not, because I like the tan interior of the the regular 635 maroon color. The only color interior in the M models is black.....
I bought the M635 myself. I was looking at the Royal blue, but the color just wasn't right, so I looked around on the net, and found out that AUTOart put out a special make-up for BMW dealers. It is a M635 in White with Black interior. I found one at a dealer in N.J., They have a boutique in the showroom, and I ordered it over the phone and they shipped it to me. It cost was $65.00. A little more that the standard AUTOart's, but it is well worth it, as it was VERY hard to come by. When I got it, I had a dealer near me do a search on there parts computer, and he found only 5 on the whole East cost of the country. I think now you may be able to order it from BMWonline.com. The description only says 635Csi, But it is an M6, and has the badge on the front grill, and on the trunk.
Once I saw it out of the box, the model is well worth the price I paid for it. AUTOart at their best. Just wanted to add my two cents on this model, as I haven't seen anyone with any pictures of this color yet. Just wanted to inform and pass along some info to fellow collectors veiwing this post. Can't wait for AUTOart's Red E30 M3.
I'm lucky enough to have three, blue and shadowline M's and green 635. Got really good deals off eBay on the last two or I would not have splurged so.... if I could only have one it would be the M version.