Do the mechanics at the dealer use a drip tube method or do they have a fancier method? I know the manual suggests the injection be retimed periodically but I've never done it. If the car runs OK I'm guessing no harm done. Or is there?

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold