I have a problem which seems to be pretty common with the alloy wheels used on the Trailblazers/Envoys.....I have slow tire leaks due to corrosion around the wheel rims (Discount Tire has been telling me this the last few times I brought the Envoy in for tire rotation and they tires were leaking pretty badly last winter). I called a local garage and they told me they could remove the tires, remove the corrosion with a wire wheel, and seal with rim/bead sealer. They charge $25 a tire to do this. They also said they can then fill the tires with nitrogen which has less waster than regular air and should reduce corrosion ($40 for all four and unlimited, free refills). Does this sound like a good course of action? I plan on having the Envoy another 2-3 years so want a solution that will last. Do the prices sound reasonable? Thanks!