my formula for calculating the size of an intercooler is simple....
a couple of variables....

frontal area on car available for intercooler, comprising of L H W.

and
size of wallet......

multiply those two and you have your size......

Bigger is always better... for car use... there is not enough space in the front of a car, to mount an cooler so big, that it will actually cause a noticeable difference in lag.... besides, the cooling of the input charge will more than negate the power-loss from lag, also the lag from plumbing volume pertains mostly to when the engine get started first thing in the morning.... once the system in operational that lag is almost negligible...