For IPSC matches I would use either your G17 or the better choice of the Glock G34. Drop in parts are easy to come by if you want to do modifications to the Glocks. Magazines are cheap, plentiful, just about indestructible and you will want a bunch to shoot in matches. I only own 1 Glock, the G34 it is my USPSA/IDPA pistol for now, have an STI 1911 ordered, it will be here in September. I really like everything about the G34, except the long trigger pull and reset, also the stock Glock sights need to be replaced IMO, again parts for the Glock are easy to find, and don't take a pistol smith to install. I personally would never consider the Ruger, XD, M&P, or any other Glock clone, possibly an H&K P30L or USP Expert. If you really want to compete maybe step up to an STI Spartan in 9mm for around $650.