When replacing the shifter in my 190E...
 

I have to buy the knob and shaft, correct? I want to replace the original with a zebra wood so that it will match the other wood in my car. It's $70 including the shaft. I can also get just the wood knob for $40, but it says "Professional installation recommended." I take it I can't just replace the knob myself? By the way, it's a 1992 190E. I would appreciate any advice on this topic. Thanks.

Do a search.
The 190e has a one piece unit. The shaft and the knob are permanently affixed to each other.

However you can buy an adapter shaft. This shaft is sold at places like www.************************ and once installed will allow you to change the knob alone.

This is the knob I was referring to:

http://store.yahoo.com/parkplacemotorcars/gearshifknob.html

As Yal said, the W201 and W124 shifter consists of a shaft which is held in place by a locking bolt at the base under the shifter console. On the other end, the vinyl knob is molded around the barbed end of the metal shaft. You won't be able to use the threaded replacement shaft since the knob you want has the long neck, and the replacement shaft is designed for the shorter leather clad knobs, like on the ML. If you want that long tapered shifter, you should get the one piece unit with the shaft.

Do you know where I can get the one-piece shifter? I can't find them anywhere. :confused:

That shaft in the picture says its for an 86-89 car. I would call them up and ask if the knob comes with a shaft attached to it. If it does then you should have no problems swapping it with your old one.

These are alwys plentiful on EBay http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7921053938&category=33703
As Yal said, I'd be very surprised if the one pictured doesn't have a shaft, it's just not in the picture. I replaced mine in my 380SE. Miserable job, took over an hour and a half! I had to take out the wood trim piece over the shifter (easy), then unscrew the stem from the socket at the base (easy), then hold the damn socket upright with my finger against the really stiff spring while attempting to thread the new shaft into it, which was bent slightly so it turned like a bent bolt (that's where the hour went!). You'll be swearing a blue streak if it's set up on the 190 like mine is....and from the looks of it, it is: