If that's the only problem about it that concerns you, then just buy a diff-drop spacer from someone like 4Crawler. They are only about $30. I wouldn't be surprised if his kit is better than some other diff-drop kits that are included with popular kits. Or I made my own from Ace hardware for about $12.

Jeff
2000 4Runner SR5, supercharger, rear e-locker, ARB front locker, 285/75R16 MT/R's, custom bumpers & skids
2007 Tacoma double cab 4x4 - stock