About 20k miles ago (& 3yrs) I fitted a set of Beru (Silicone-Blue) ignition leads to my 91' Volvo 480 Turbo Auto. These were purchased here in France (before I discovered that GSF are cheaper inc delivery

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These leads were supposedly good for 50,000Kms.
Anyway at about 18k miles the king lead had corroded through & snapped leaving SWMBO stranded about 4 miles from home. Luckily I had kept the old king lead as that looked worth keeping when it was replaced. A good choice!
Another 2k miles on & the Beru jobs are arcing slightly - time to replace! The old king lead still looks worth keeping as a spare! So Beru silicone leads, would appear not to be up to the job methinks.
I contacted GSF, expecting a set of 'Mann' leads & after a slight glitch by another staff member, Julie McColin at Heathrow dispatched my order.
I have received a set of BERU leads, but these are shown as OEM & are black, so not too worried - they should be good.
One question - there are 6 leads in the set. With a 4-pot engine & king lead that makes 5 required. Before I fit them, is there a reason for having 6? Also which one should be 'dis-regarded'? The GSF part number is V92614, which shows as for my car.