A couple of things that might help...
First, for IDPA (and for real-world carry) I'd definitely recommend a Mk III (current production) HP, due to the vastly superior sights and safety levers, as has been mentioned above.
Second, you'll need at least four, and preferably five magazines-one to "charge " the gun (chambering a round, ejecting the magazine, and then inserting a fully loaded magazine), the fully loaded magazine in the gun, and two reloads, plus an empty magazine to be inserted after a firing sequence to enable the hammer to be dropped after "showing clear" (due to the magazine safety). Theoretically, you could use an expended magazine for this, but you might not fully expend a magazine in a low round count scenario-so you're just better off having a dedicated empty magazine to use. Of course, if you're using a 9mm Hi-Power with 13 rd magazines, you'll only need 4 magazines, as you can only have 10 rds per magazine-except for the first magazine, which you can load up with 11 rounds, to achieve a chambered round, leaving you wit 10 in the magazine.
Third, while I've never personally had one, actually the reports on the Charles Daly guns have been fairly good (and, for all practical purposes, a Charles Daly IS an FEG, albeit one with a set of Uncle Mike's grips and XS sights, assembled in the US). Expect them to have a pretty heavy and gritty trigger, though, judging by the several I've handled. They will be your least expensive brand-new Hi-Power choice/clone-but they've been discontinued, as apparently FEG has gone out of business in Hungary recently; I still see that brand new ones are available in my area. Otherwise, cost wise, your best bet might be one of the FN-rollmarked Hi-Powers, which FN dumped on the market when they decided not to concurrently compete in the US with Browning and their Browning-rollmarked Hi-Powers. I believe that there are still brand new FN's still available, although most of them currently available seem to be in .40, and have the SFS hammer system. Thery're usually in the $450-$500 price range ballpark.
Fourth, you'll need a decent holster, one that meets IDPA criteria-see
www.idpa.com.-and while you're there, download the current IDPA rulebook. The preponderant holster choice in IDPA seems to gravitate around the various kydex selections, due to speed and durability. My own recommendation would be for Blade-Tech- but there are plenty of excellent holsters.
Fifth, you'll also probably need a double magazine pouch. While IDPA does allow you merely to keep your loaded magazine reloads loose in a pocket, virtually all opt for a magazine pouch. An excellent, inexpensive one is The Wilderness' "Double Ugly"-see
www.thewilderness.com.
Sixth, other than the need to retain the magazine safety to be in compliance with IDPA rules, the only real "hazard" in using a Hi-Power in IDPA (or real life!) is that accomplishing a fast reload requires practice, due to the square shape of the magazine and the magazine insertion point in the receiver butt. I'd recommend only using current factory (Browning or FN) magazines, due to 1)their reliability, and 2)their silvery external finish, which is some sort of a Teflon coating, providing weatherproofing AND minimizing the drag of the magazine safety plunger on your triggerpull, and 3)their "mousetrap" extrnal spring at the butt of the magazine, ensuring a forceable magazine ejection. They're made for FN/Browning by MecGar-MecGar sells them also under they're own label, but the MecGar ones, while reliable, WON"T have the "mousetrap" spring.
That's all I can think of off the cuff-hope it helped!
Best, Jon