Congratulations on your new Crosstour
My 2011 CT EX-L is undergoing a sound system upgrade at this very moment.
I'm keeping the factory radio and navigation, back up camera and diagnostics display, but upgrading the amplification and speakers.
I asked for pictures to be taken during the install, I hope to post them after I pick up the car.
I am also planning to update the alternator to a high output model.
Then we'll see about paint accents.
There aren't any engine mods that I am aware of except cosmetic options.