The consensus is there is no difference, except on the later G firmwares past P, like G7T9, it doesn't work with CD-DVD Speed. If you want to flash with a regular exe, I can send you G7P9. Just click on the exe, point to the burner, have no media in the burner, and flash it and wait for it to ask you to reboot. If you burn with that awhile you could cross flash if you want. Supposedly the U firmware has optimized some DL burning.
Someone posted this link to their site for G7P9.
Nu-tech also list the OEM G7P9 firmware. I assume it's good for any OEM.