With the ESC, there are usually only a few concerns. The specifications will list the battery type(s) of course (Lipo/Nimh, etc). The battery "size" will also be listed (2s/3S, etc). Also listed will be the maximum motor size (most often listed in "turns").
For example, here is an exerpt from the specs for a Novak GTB2:
Motor Type: Sensored Brushless
Input Cells: 1*-2S LiPo/LiFe or 4-6 NiMH
Motor Compatibility (#1749 model) 540-Size: 3.5-turn or higher sensored
This tells you a few things. 1st, you can't run a brushed motor or a non-sensored brushless motor with this ESC. 2nd, if you connect it to a 3S Lipo, bad things will happen quickly. 3rd, if you try a 2.5-turn motor, it's not going to last very long.
You CAN run a low MAH/low C 2S Lipo with no problem. Your motor performance and/or run time may be reduced, but the ESC will handle it just fine. Or, you could put in a high MAH/high C 2S Lipo and observe pretty awesome performance and ridiculous run times
One thing to note...with a 17.5 motor, you're not likely to notice any improved performance with a 100C battery over say a 50C. Of course you won't notice any lack of performance either. If you already have 50C-60C-70C batteries, I'd save the cash and run 'em!
Sorry for the long reply. I'm bored