I'm back

Hello dear people,
After a few months of break, I'll call you back.
My 4.2er still runs, now have 184,000 km on it and a few questions to you.My last inspection is 13 months back or 30 000 km. I don't let Audi workshops get to my V8 anymore, but a few things are due.
What about the spark plugs? The other day, he jerked at the gas-gathering. Can that be due to the candles? He's starting off great and still pulling well. When should I change the candles?
I had a bigger gearbox repair a year ago,
Oil pump , engine and transmission rings have been replaced.
He doesn't lose oil, but when I switch, I get the impression
If I milk it right, which I do very rarely, the gearbox switches on quite normal, only when driving slowly it just jerks a little.
Should I have the transmission screen made? I know that this is a sensitive point in the V8 transmission and therefore I'm worried
Thanks for every tip.
MfG,
Frank