W126 distributor cap, plug wires info

[unkl300d]

Hello,
my 1989 300SE has intermittant stumbles during idle. Like explosive burps.
(gas mileage seems to have dropped a bit)

My Beru silicone wires have 36K miles on them as does the distributor and rotor since brand new.
Should the wires, plugs and cap/rotor last longer?

Does the dist. cap come off with a 5mm hex? What tool is best used to manage the final third hex nut at the cramped bottom?

What is the best way to pull off the plug boots from the spark plugs?

I've researched the past archives and have a general idea on some stuff but seek some more updated detail.

Thanks car has 136K miles on odometer