I'm new to competition shooting (IDPA, USPSA, 3gun) and getting familiar with the different divisions.  I have a Glock 34 for IDPA SSP and XDM 5.25 for IDPA ESP.  The PPQ M2 5" looks like a nice pistol for competitions.  The one thing that bothers me about it is its 15 round capacity (the G34 had 17rnds and the XDM has 19rnds).  I know in IDPA, that really isn't a consideration with 10+1 capacity limits, but if I wanted to use the same gun for steel competitions and 3gun, its something to think about.  I see Walther has factory PPQ M2 17 rounds extended grip mags for sale (I don't know why this 5" competition model doesn't come with them standard).  Does anybody know if going with a factory extended mag like this would have an IDPA/USPSA rules considerations or throw you into a different division?  Example, if this gun is SSP legal out of the box, would just using the extended mag force you into ESP even though you still only load 10+1?