Biggest headache on the 700R4 is getting the TV cable linkage setup correctly.
4L60e - yes you need a controller they are not all that expensive anymore - they do need a TPS sensor - if your running a holley - it bolts on otherwise a remote mounted one - most of the controllers you turn it (key on engine off) on with the throttle closed - push a button, stab the throttle WOT, push the button - done. No fiddling with cable and linkages and no chance of getting it wrong and frying a set of clutches.
