The 108/109 body is a fine, fast, and fun four door auto. The only ones that came with air suspension were the 300 SEL and the famed
6.3. And unless you have money to burn models with air suspension can be a bare. I prefer the 6 cylinder cars for several reasons;(except the 6.3 WOW!) easy to maintain and repair, better mpg, less tempermental (I don't know why, 4.5s just can give you hell), and for me I like a manual and you can still find some with a four on the floor in six cylinder cars.
The neat thing about these cars is that they can be daily drivers, and less costly to restore than SL or SEC coups or cabs, far less! I also recomend finding a long weelbase one, lots of room, almost limo like. Right now I don't know of any for sale
but keep your eyes peeled there are a lot around, tucked away in back yard sheds.

Good Luck,
Mike

62 220Seb coup
72 250C
65 600SWB