I do not have an answer for you, but I have been playing with MicroChip XC8 (free version). So far the speed and code size seem about the same for similar functions.

Compile time is much faster though. So other than cross platform abilities and add in trouble like you are having, I do not see much of a reason to switch from PBP. I know,,, the dsPic is the reason.
Is that the reason you are moving to "C"?