for 01-04 the C32 is not available in manual transmission, and the C320 is available ( 2003 ) in manual form.
All this info is available at the www.mbusa web site. They have a section that list models going back some fifteen years.

Mercedes does make their own transmissions, and from what I have read the 2005 model year is the first time in a C-class the lever action of the six speed is good.

The drawback to the C32 engine is high fuel consumption and high center of gravity on the engine both caused by the superchargers. Mercedes is phasing out supercharging for turbocharging.

I know someone who has had a C240 returned under Lemon law, some of these cars are made in Brazil.

My C240 has been flawless, made in Germany. The interior is very airy and relaxing. The best part of the car is it's ability to cruise at high speed for a couple of hours at a time in great comfort

Some people (car magazine articles ) have said that they prefer the engine power delivery on the C240 better than the C320. This seems to be more acceleration performance as opposed to steady state high speed cruising.