MBZ model identification

MBZ model identification

Hi Guys,
New member here. Just wanted to get some very basic information under my belt.
What does MOT stand for? I know this is Brittish but it's been bothering me and I figured one of you would know.
How does MB arrive at their model number designations? Example W124. R107?  Does the R stands for roadster? what does the "W" stand for? Is the numbering sequential from some master engineering book of project numbers?
And this is the big one. Has anyone put an (choke) American V-8 into one of the R107's and been able to get it to legally pass smog requirements?
I hope this doesn't start a major discussion
BTY I'm currently restoring a 85 380sl and finding that this site is great source of information.

Thanks.
Just having fun.