a set of OE-type replacement plug wires from the auto parts store is less than $40. Your time and aggravation factor is worth more than that. Just go buy a set, install them yourself or hire someone to do it, and be done with it. The "one plug wire at a time" philosophy at GM has screwed many a customer, it's screwed GM under warranty too but where the unscruplous dealership (and there are plenty of them) makes it up is by pulling the same stunt on out of warranty vehicles, charging the sap customers several hundred dollars a pop with every service trip. If they ever tell you there's a bad wire you tell them to replace the whole set and you'll pay the difference. Don't let them bend you over.
Getting to and removing the spark plug boots takes care, finess, and the proper tools and even then you stand a chance at damaging one, particularly if they are the original wires from the factory that always seem to be permanently bonded to the sparkplug. It would seem that GM is not lubing the boots with dielectric grease on the production line wires. Even on pre-lubed wire sets I recommend taking a cue-tip and making sure the lube is swabbed around the entire boot surface; they often just smear a dab on in one spot. My philosophy is that since the only time I'm likely to remove the plug wires is to replace the plugs or do major mechanical work it's cheap insurance just to install a new wire set too. This allows you just to yank the old set quickly off without concern for their condition.
Further, the OE type wire set is more than adequate for all but the most hardcore racing applications. I've seen more problems with aftermarket wires than OE; they cost more so people are less likely to consider replacing them. Don't waste your money, there is no real performance to be had with aftermarket wires, just get the OE type and if there is any suspicion of damage then shell out the $40 and replace them all in one shot. Your situation is just one of many examples on why this is a good practice.
