you need to wire both the johnson and the lightning pump. the johnson pump only requires you drill 1 hole in the stock location and use the johnson bracket. no larger hoses are needed. factory hoses fit just fine. all is needed is new clamps.
as for the flow thec pump can only flow as much as the hoses and the h/e will allow. a larger h/e will drop the temps and allow the pump to work more effectivley.
the bosch flow 4.4 gpm and the cm30 flows 6.7 gpm
the MAIN reason for using the johnson cm30 over the bosch pump is longevity. the bosch has a proven history of lasting maybe 30k. call it the bosch or lightning pump its 75$ to $85. spend 149$ for the johnson pump and forget it. it will outlast the car

when i did my pump i simply used the same electrical connector from the factory pump and wired it to the johnson pump. no splices no cuts to the factory harness. plug and play