They make a big difference on shift firmness on my 85 300d. I ripped out my egr to get rid of leaks. Also got rid of the vacuum amplifier among other odds and ends. When I was all done I adjusted the firmness of my shift by adjusting a single orifice size on one of the transmission control lines...it was either a bleed off or the line to the modulator or VCV. I cannot recall. The end result was I could increase or decrease the vacuum seen by the transmission modulator. I did this on previous cars using the adjustment screw in the VCV but I decided to try with the handful of leftover orifices after the egr delete.

__________________
79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles