It is a mandatory for me to have Viper4Android installed, so I've always used it on every device.
Norally, enabling Viper4Android for Tunein Radio app was quite easy, as we simply had to install this mod (I can't find the thread where I've downloaded it from, if You can, please send me the link so I can give credits to the dev who made it) and after that just install Viper4Android.
However it wasn't working so well on every custom (non-sammy) ROM. Installing the previous given mod made it unable to make any phone call, as there was completely no sound during a phone call.
So I've finally found a way to enable Viper for Galaxy S4 and keep the sound working while calling someone.
Here's what You have to do (You have to be rooted and have CWM or TWRP installed)
1. Download this and put it to Your sdcard
2. Reboot Your device into recovery and flash the file (it will wipe dalvik cache)
3. Turn on Your device and install Viper4Android libraries.
That's it, You're done.
Now You can listen to Tunein music while using Viper4Android.
REMEMBER: I'm not responsible for any damage of Your phone. You do it at Your own risk.
A nandroid backup is recommended