We do honor Bilstein's warranty, and can help with any warranty issues that may arise from Bilstein's 5100s. These strut assemblies are only capable of 2.25" of front leveling, however, for most leveling applications, we generally recommend a 33x11.50" tire or close metric equivalent. That being said, you can fit taller/wider tires depending on what wheels you're using and their specs. As to what specific tire you should use, that really depends on what kind of traction you want off-road vs. what kind of ride comfort you want to keep on-pavement vs. what you're doing with your truck. Your best bet would be to call us directly at 623-434-5277 so we can get more specific with what you're trying to do and what you do with your truck.