I have a P226 E-squared in 40s&w. I want to experiment with different grips, but am not sure what modifications must be done to the pistol to enable it to use original P226 grips. I have read that changing from an original P226 grip to the E-squared grip requires changing some of the internal parts near and including the mainspring, but what about going the opposite direction, i.e., from E-squared grip to original Sig grip?