I have a great MB mechanic that has yrs of experience. I got lucky. New parts cost prohibitive... he found a great set from "used" yard...fairly inexpensive, but do not know if they are the 90 and above upgrade. Do not have final bill yet. He is doing the oil seals as well, since cam is off. I am hoping this helps with smogging in california.

He also told me it helps with catalytic converter also...no oil passing seals to get in exhaust, so cat purges itself(oil is bad on cats!)....

Let's see...I will post results
Warren