Intercoolers of the same config. were used on early model P-38's. They ducted
pressurized air along the insides of the leading edges, then into the carb.
They all had problems with cooling efficency and leaks.

Several famous Thompson Trophy (sea/float planes) winners used surface
radiators to some degree. Most notably the Supermarines. Don't know what kind
of problems they had, but its worth a look, and a grain of salt.

Harry