Can someone please explain the differences between the various TT engine options?

I've been researching different TT engine options and I'm still a bit confused about the differences. As someone who's considering purchasing a new TT, I'd love to hear from others with more knowledge on this topic - what are the key distinctions between the 2.0T FSI, S-line, TTS, and other variants? Is one definitively better than the others for performance, fuel efficiency, or handling? Any insight would be greatly appreciated!