Far as I can tell Viper just doesn't work on any 4.3 ROMs. Tried a number of them. You can find a few in this thread who say it's working for them but I'd say there is some element of their ROM that makes it work (and it's not the build.prop edits!).
I just switched to this 4.3 rom and V4A works great on it. The thing is, this rom is based on the latest manufacturer release for my phone. I'll pass on those CM roms. People in this thread have nothing but problems with them.
Sent from my SCH-I605 using Tapatalk