Default [Q] Should I flash my G900I with a G900F ROM?

I've flashed many different ROMs over the years and never had issues but I was curious as to whether the different modem in another variant would cause issues with LTE?

The G900I I have has it's dock locked so can't change anything and the always on voice (Hi Galaxy from sleep) doesn't work. These 2 issues seem common with the G900I. Here in Australia our LTE bands seem different to most other countries so I need to know if I screw with the baseband etc, will I have issues with network speed?

Thanks