the ad says:
BMW 645 CSI 81 Rare, BMW Factory Turbo, only 10 built. BBS WheelsVery Fast!

Not sure exactly what we have here, and i can't find much info on an 81 645.

linky?

it is a newspaper ad. there is no link and no picture associated. I typed exactly what this guy put.

I suppose it could use the 745's turboed M30, but as far as I know, there was never a factory use of the M103/M106 in an E24 chassis. He could have had the swap done.

Sounds suspect, got a VIN ?

There was the Alpina B7 & B7S but they'd be advertised as alpinas.

Cheers,
Iain

the ad says:
BMW 645 CSI 81 Rare, BMW Factory Turbo, only 10 built. BBS WheelsVery Fast!

Not sure exactly what we have here, and i can't find much info on an 81 645.

There was no "factory" 645 that I've ever heard of, and I highly doubt that car would have been produced in 1981, ahead of the 745 Turbo.

Most likely you have a car that had the motor/turbo setup from a 745 transplanted into an early Six. If done well, it is a desireable car. I thought at first it was one of the Munitech (http://lalacars.com/bmw82~645.htm) cars. Take some pix and post details if you can...

Munitech is the first thing that came to my mind as well.

A lot can happen to a car over the decades, and as owners change, things amazingly become "factory" during that process. Many times the owners don't know they're misrepresenting something, although there certainly are times when they do.

I'd certainly like to see some pictures of it. :)

I'm assuming you're looking for the Pirelli/M5 poster not the ad? (http://cgi.ebay.com/1987-NICE-BMW-M5-Floating-on-Pirelli-Tires-Print-Ad_W0QQitemZ320078757178QQihZ011QQcategoryZ13572QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem)

I'd set up a "favorite search" in eBay and it will notify you when something gets listed...

Yeah, looking for the poster. I want to get it for the father-in-law as I am sure he would LOVE it. I haven't found one on Ebay so far, but I've also been away from it a bit recently.