Hey guys, I'm still new to xd's so please bare with my lack of knowledge. Is it true that changing of barrels / mags is all it takes to change calibers of the xd? Are there internal differences in the guns that would make it less reliable after a conversion? I am wanting to get a .40 s&w service and throw a 9mm conversion on it while target shooting, and keep the .40 cal at home for defense. What is the most reliable conversion barrel? Is it recommended that the slide is changes as well? .40 s&w mags are the same as 9mm ones correct? Sorry for the barage of questions, I just wanted to be 100% sure before making the purchase. Thanks in advance!