Well Ron,,
Tonight I installed the Stock Bosch Plugs.
Ive had a rough idle and never felt the best about the Bosch platinum 2's.
So I only ran them 5,000 miles. I think my mass air flow problems may have made them foul early.
At least they were only $4 per cyl each so I only blew $24 plus tax.
2/21/07 update. New stock $100+ plugs still did not take miss out of idle.
2-1-8 UPDATE : I replaced 3 of the ignition wires where my records show I picked up some misfires based on my code reader. I am down to a rare occational mis fire. I sat in my brother in laws 2007 Suburban and it idled worse than my 1999 with 130,000 miles. I decided my rough idle is so small I can ignore it.

__________________
Steve Danville
what i did myself.
CPS
rear shocks
MAS x 3.
SparkPlugs (twice)
Fuel pump & Filter
Window switch
replaced both failed horns with Honda horns.
Cleaned ERG Tube
Oil changes
Oil consumption Fix
Brake Pads
A/C Recharge
Anti-Freeze change X 2.
Front Shocks. Monroe. $90
Mercedes Warrenty Work:
Harmonic balancer,power steering clamp. Cat converters.Drive Shaft Bearing.s
Replaced Outer Lower Tie Rods and front lower ball joints at 156,000 miles