I would appreciate someone pointing this newb here to a good resource that helps explain what is and what is not legal for IDPA. I'm a new member of IDPA, have reviewed the rules several times, and am still confused as to what upgrades/customization one can do without running afoul of the rules. In particular, I'm trying to reconcile the ESP modification rules to what is on offer at both CZ Custom and Cajun Gun Works. Thanks in advance.