Most of the differences are minor. The external lighting is a bit different. The turn signals are amber inserts located in the lower part of the outside of each tail light pair. They also have rear foglights. European law dictates that if a car has front foglights it must also have rear foglights. There is a side indicator lamp on the front quarter panels just under the upper crease of the side vent. It appears to have a clear cover with an amber bulb. The rear indicator lamp is also amber not red. The gages on the dash are in metic units such a kilopascals (kpa) for pressure readings and celsius for temperature readings. The speedo goes to 300 units instead of 200 units like the US version. The car also has a front and rear tow hook by European law. The Euro vettes also have headlamp washers because of European law. They also come standard with Z51 suspension. F55 can be ordered on Euro vettes but according to a couple of Corvette engineers I spoke to at Carlisle when F55 is ordered the Z51 springs and sway bars are downgraded to base suspension pieces. The brakes and the tranny (MZ6) stay.
When I had my 2002 the only colors that were no cost in Europe were black and white. All other no-cost US colors such as torch red cost extra. That may have changed by now but I am not sure.
From the European C6 brochure I have it appears the convertible comes standard with power folding top. It also appears that the HUD is standard. Side airbags are standard.