[Q] G900I Taiwanese ROM to Australian ROM? topic

Hello,

I'm about to purchase a Galaxy S5 G900I on eBay from Taiwan and I am was wondering if flashing the Australian equivalent ROM on the device would work? I am planning on using this phone with Virgin Mobile (who run off of the Optus network) so would I have a problem flashing the Optus Australia ROM? Should I just flash the generic Australian ROM? Or would doing either of these brick my phone?

Sorry for the noobish question and thank you in advance!

Cheers,