I believe this ROM has the 900Mhz / 2100 Mhz modem.
If you are in the USA:
To fix your 3G, this should do the trick:
Download to phone.
Boot to recovery (TWRP).
Wipe dalvik and cache.
Install file Modem-850.zip
Wipe dalvik and cache again. (trust me)
Allow at least an hour for the signal to stabilize. with your WiFi disabled - use your data normally. This should give the same connectivity as OEM. Try setting your APN as Bearer Unspecified if it is giving you issues.
After this, bluetooth seemed to work much better, but it still took forever (and multiple attempts) for devices to pair. Once paired, everything has worked smoothly so far. To pair, I played with turning off WiFi. Once paired, it was GTG. I have no Bluetooth LE devices nor do I connect automobiles, so this may not do it for you, but it is worth a shot.