5.1 ROM with working bluetooth, any help?

My sister-in-law Galaxy S3 was getting old, so I installed for her Temasek 12.3 rom, and she loves it very much, except that she depends a lot on Bluetooth for car/headset, and with the default ROM and kernel the bluetooth is troublesome: freezes, doesn't work always, needs a lot of reboots.

What ROM/kernel combination can I put to have a stable device with a working bluetooth?