420 SEL: Timing Chain

[Randy]

I have learned there are metal replacements for the three plastic upper guides: are these good or bad?
I prefer a replacement chain which has a rivited closure (master link), but all the ones I have found have a master link with C-clips; the one shown in the factory manual has C-clips as well: good or bad?
I found a local shop; place looked nice and clean;floors painted white, etc. so I asked about changing my chain and the three upper guides. They wanted to change the cam sprockets also; total about $600 labor, about $300 parts, incl. tensioner. Then they stated, "We don't usually work on cars that old, but..." well, that blew it for me.