Hey to each his own (it is supposedly still a free country) but I'm going to say this IMO. The shield is a easily concealable carry gun and it has no role in any competition (maybe the rare BUG side match) or really much serious target shooting for that matter. If you do anything to that gun other than sights, grips, maybe a little trigger smoothing or general cosmetics you are asking for trouble if you ever have to shoot someone with it. I'm not so sure even the so called duty/carry APEX kit has any place in a carry gun. No different than its a bad idea to use any ammo for SD that is hand loaded or non mainstream commercial. The guy planning on using APEX to circumvent MA law (no matter how archaic) is just asking to get the shaft. Every other issue aside that could be a firearms violation with a mandatory min if it was ever discovered in an investigation.

Trust me I'm the first to spend too much money tricking some of my guns but not the one(s) for carry. Just too much great stuff these days, that does not belong on a carry gun, that really came about because of the demand for competition parts. I really don't think there would even be an Apex or much of the cottage industry if not for IDPA, USPSA, 3 gun etc. With all the local/state/federal laws we all walk a fine line exercising our 2nd amendment rights. I just prefer to not end up in jail or sued into oblivion.