I use the 09146 wireset on my 300SEL and either NGK TR5 plugs or Bosch HR9DC...both seem to work fine. Car just rolled 300,000 miles so I must be doing something correct.
Seeing how this car turns right around 3000rpm @ 60mph, you should consider replacing the cap and rotor while in there. Probably your fan belt too while inspecting the idler pulleys. Valve cover gaskets do not seem to last too long for me either.
Keep us posted on your decision.