You can change a car transmission with a flat screwdriver, but it need a bit more work Same goes for compiler. Compilers are just tools, there's nothing bad using more than one, use the one that fits your requirement.

If you feel you may have some requirement for it in the future, I suggest you to port some existing libraries. There's some in C18 on Microchip's website. THere's also some pre-canned solution like ethernet module (Rabbit, Charon, Lantronix etc etc).