For me, it's got to be the GT Limited. Mainly because of the Autonomous Emergency Braking and Advanced Smart Cruise Control. The AEB can really save your bacon. My last rear-ender , about 8 years ago, happened on a dark winter morning making a right hand turn behind a Volvo. The light changed, a pedestrian stepped out in front of the Volvo, the driver stopped, too late and dark for me to register, and the rest is history. If you drive regularly in stop-and-go traffic, I believe AEB is a must and really should be installed in all cars, just like ABS. I am also looking forward to the HUD. And the 360 degree camera system is nothing to sniff at either. Sure, in 5 years, these things will probably be standard in all cars, but I want it now. If you have the budget, go with the mostest.

My comment on the audio system won't help you, because you probably know about it already: The GT Ltd. has 6 speakers more than the GT-Line. So it will be what - louder? Coming to think about it, the GT Ltd. has a woofer under each front
seat, do the other models have woofer(s), where and how many. That may be the biggest difference. You may want to investigate.