[1badgmc]

The VIN is an X, so it's for sure a 1999 model year. How crazy. I always thought they were 2000 only as well.

Your stock tire size should be 255/70. Looking at your pics, the tires look like they might be a little bit shorter.

It's also normal for the 2wd 4-door Tahoes and Yukons to sit high in the front. I had a '99 Yukon long ago. I measured it before I lowered it and it was 3/4" high in the front at stock height.