I didn't DIY, but my Indie shop did and it did WONDERS for my car, including making my car drink 1 qt of oil every 600 miles. I'm not kidding.
1994 C280, dark green metallic
1991 190E 2.6, Black
(sold to another forum member)
2003 Chevy Tahoe LT, Redfire Metallic
1989 Mustang GT Cobra Convertible