Sin, on MY99, there are no spark plug wires and no distributor. The "regular" coper wires come right up to the spark plugs and connect to individual high voltage coils which sit on top of the plugs. The problem described here is that the jacket protecting the coper wires from the intense heat of the engine head has been underdesigned for the application and falls apart leaving the coper wires just hanging there and at risk of touching a hot surface and melting the insulation and shorting to ground. Also, even on an old-style ignition system, I do not think that the spark plug wires have a 2 year life span. Most people here reported very long life span for the spark plug wires, in fact (over 100K miles and 5 years).

What I would do is try to find a better insulation for those wires, i.e. do the jon of Volvo engineers and send Volvo a bill for hours spent on the task just for fun.

Cheers.