Hi to all, I recently bought a truck from a friend and was wondering what would be the best mod next.It is a 99 z71 silverado ext cab with these mods: 03 lq4,kn cold air intake,zo6 cam,42lb injectors,upgraded fuel pump(he could'nt remember what kind),built tranny with shift kit and corvette servo,hollow cats and single to dual flowmaster muffler dumped, 3in body lift,22in chrome rims/305 45 nitto dune grapplers,and still has the 5.3 computer tuned by his buddy's hp tuner.I what to get a efan but what all will I need for it to work? Any other suggestions?