yes the 4.8is has those problems and some body problems too.............the problem with the heads have a lot to do about the oil You use and how often You change the oil, if You find one with low miles You can save the heads with knowing You to have change the oil with a high quality oil ,lets the engine warm up on cold days, keep the CCV clean , and of course run a good fuel and also doing Chevon fuel injector cleaner every 4k miles.............You have to be careful with both engines[4.6is,4.8is], I have the 4.8is now running strong ................the air ride is cheap if You go with Arnoff high quality strut and air life time warranty.[$420 after You return the old one].

good luck

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2006 4.8IS
65K MILES
PURCHASED 7/13