Land Rover Repair: Range Rover 99 4.6 HSE spark plug wires, rough shape, light flashes

Question
John,
Good day.  My engine is running rough and the check engine light flashes.  I checked the spark plugs and they are in pretty rough shape. Dealership has suggested that I replace wiring as well.  What should I expect as a reasonable cost for this sort of repair?  I have been quoted $850.00 US.  This seemed a bit high but I do not know what is involved.  Any wisdom.  Thanks.

Answer
Proper replacement of the wires is a 3+ hour job.  The 8 wires cost about $25 each.  The 8 plugs are about $15 each at the dealer. The dealer may also be planning to replace the coils ($250) while in there - that's common.  Hence the price you were quoted.