When I started shooting IDPA in 1998, I shot what I had, a G26. Then eventually I upgraded to a G34.
But the reality is that the gun isn't worth that much time. I've seen Dave Sevigney win with an out of the box G17, just because he could.
The funny thing, is that all of the G26 time has made it so I shoot it better than the 19. It points differently because the bump in the backstrap is higher up than on the 19.
Short answer to the OP is simple.
Shoot what you have.
If you need a holster and mag pouches, just go on Amazon and get the proper Fobus for your handgun. It will cost you about $40 total. And you will be good to go. Remember, the latest greatest holster will save you maybe a quarter second per run. At this point its going to be taking you well over a minute to complete most stages.
Also, remember, you can't miss fast enough to win. Go slow, focus on a smooth trigger press and the speed will come.