I tried the 2.5in lift kit with the spacers and blooks on my previous Sierra, it was perfect, now, I have a crew cab not extended one, and it will need higher lift to look nice, but I didn't try the 6in lift, which is more complex having all those componentes to be installed, My quastion to the experts is :

Does the 6in lifts have failuer issues or tendency to break or known problems? disadvantages ? would the work as good as the simple 2in lifts ? would the transmission be affected by the new angle of the drive shaft ? will the full throutle have more impact on the transmission?

If I am going to get 6in lift ? is there something I should look for in any lift ? ( special part that should be included etc. )

Thanks