Just did this 2 weeks ago. Billybob's on it except there's no need to unbolt the reservior, the hose is an easy fit with the tank in place. The CD says to remove right front wheel which I did, but it may be possible to do it with the wheel on.
My temp had been running between high 80's to just under 100 and after replacing the overflow tube it stays steady between 80 and about 82. Must have some impact on system pressure and overall function. I had assumed it was only to catch excess coolant.
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)