Using Sprint S3 on Textnow, want Textnow Rom to improve call quality

I use TextNow phone service, and I am happy with it. But I recently switched from my official textnow phone to a BYOP regular Sprint S3. The activation worked fine to textnow and data works great, but I'm having bad call quality. It was bad on the stock sprint rom and is still bad on my custom rom that I have running now. Luckily I don't use the phone for calling much, but when I do need to use it, it's a real pain in the ass.

It is my understanding that textnow somehow tweaks the phones they sell, either by adding apps or customizing the rom somehow so that it helps improve call quality. Since my phone wasn't tweaked by them, it is lacking those customizations.

I'm hoping someone out there may have a backup of their official textnow s3 or something that I can flash to mine so that it would have optimal performance.

I do remember seeing an "enflick" app of some sort on my old textnow phone that I figured helped with these exact issues. If I could manage to copy this file over to my S3, maybe it would help, but I feel since it was tweaked/made for the LG it may not be optimal for my S3.

Thanks so much.