New THX not for everyone - beware!
I have a 2011 MKX with THX. LOVE the awesome sound and deep rich bass it puts out, really far better than any other factory sound system I've heard, and most people that hear it agree.
However, when I got into the MKC and turned up the new THX system, I was extremely disappointed ... no deep end whatsoever. I thought it was defective so tried another; same thing.
If you like deep bass, I suggest sticking with the standard premium stereo and save the $1000. The standard 9-speaker system has a subwoofer for deep bass response, surprisingly the new THX system in the MKC has No subwoofer.
I am in the car audio business, you simply cannot get any kind of descent bass response out of 6.5" door speakers - impossible, many speaker companies have tried, all failed.
So for what it's worth, if you like pure clean sound, with crisp brilliant highs, and don't care about bass, by all means go for the THX, it's an awesome system if that's what you like. But if you like the deep rich "boom" that only a subwoofer can deliver, stay away, you will be disappointed.
I ordered my MKC with the standard stereo, and was ready to dish out the $1000!