The grads of higher powered residency programs will always have more job offers simply due to rep and the attendings' connections in the field. Those programs have a good rep due to good alumni, and those alumni have paved the road for you. If a 3rd year resident from UPMC and a 2nd year from a PMS-24 no-name residency applied for the same job, it'd be no contest. Then again, the guy from UPMC would probably wouldn't be applying for jobs in the first place; he'd more likely be sorting through 10 offers and finding the one he liked best.
GPA is important but not the only thing; clerkship and interview are probably more important. You just want a GPA high enough to get your foot in the door and get the clerkships you want. In terms of what GPA that is, I don't really know, and it depends on which pod program you attend and which residencies you are trying for. At the more well regarded pod schools, you might need a 3.0+ to get all of the clerkships you want, and at lower rep pod schools, you might need more like a 3.3 or 3.5? Again, there are exceptions to every rule. There are probably 3.8gpa people who do virtually nothing but study and will have a dry personality that'll kill them on clerkships. Also, there are probably 3.1gpa people who are very involved, good at teamwork, and great with patients and co-workers. There might even be the occasional 3.5gpa person who used old tests as a crutch and fails boards; you never know.
Just do the best you can in classes right now and build good study habits and motivation to read extra above and beyond; you will learn more about residencies as you go. The only way you can cripple your residency options is if your GPA is really low or you don't pass the boards; that's pretty much game over at a lot of good programs and you will probably find yourself scrambling for the residencies nobody else wanted now that the student : residency position ratio is heading towards 1:1...