I don't like the Amuse trunk, I agree with Kwando on the statement that it doesn't flow with the car.
I also don't like the Performance CF splitters and spoiler either, not that the parts look bad. The car has enough CF on the roof, it starts looking a little aftermarket / add-on.
For me the biggest cosmetic upgrade is to lower the car on some springs, add some spacers and do a window tint. But that's just me. That is what I will do to my car as soon as she arrives.