2000 cherokee sport with a skyjacker shackle lift, 2''. came with replacement shocks and front spring spacer and of course..extended shackles...i have a set of 3'' leafspring lift blocks sitting in the garage...the urge to put them to use is great..i need new leaf springs cause these are sagging a little.what are the consequences of putting these on?what do i have to pay attention to as far as drive line and suspension,steering? need as much info as you can throw at me