WHM suggests disabling these php functions...

[PrimalPrime]

You should consider disabling commonly abused php functions, e.g.:
disable_functions = show_source, system, shell_exec, passthru, exec, popen, proc_open

Would disabling any of these likely cause problems for SMF?

Thank you very much

[vbgamer45]

Would not cause any major issues. Maybe with hostname lookups for banning but thats it.

[PrimalPrime]

Thank you very much. Works fine.