I have Herminoe in the shop tonight and they say she needs a new set of glow plugs. I replaced them around 55,000 miles and now have about 86,000 miles. Does only 30,000 miles on a set of glow plugs sound right? The stealer is quoting around $430 to replace, not sure if that includes the harness too. Just seems like a year con't go buy with at least $600 into this bug. Is there any way to make them last longer?