[Q] Attention Drive Link users. I currently have NJ1 firmware.. Is there hope topic

I picked up a used AT&T S3 here in NY because I just installed an Alpine ICS-X7HD in my car. The S3 had the latest NJ1 installed. I was able to root the phone OK. My research has lead me to believe that I won't be able to get any version of Drive Link running on Android 4.4. Research also seems to suggest that I can't go back to the LK3 version either due to boot loader changes made from Samsung and AT&T with the 4.3 update. So I'm looking for advice from the forum experts on what I can do, if anything to get the phone downgraded to a Jelly Bean firmware. I am hoping to hear from someone who has been able to do this before...go from NJ1 to LK3.

I am comfortable using Odin and adb. Let me know if you need any other specific information.