In the performance data I've been crunching the Spixteen ranks with the other perk rides (sometimes exceeds them), and it's near impossible to change the modifiers for the performance categories to achieve a different result. It's faster than most and improves with altitude, it climbs with the 109s, its roll rate is 2nd to the 190, it packs a punch with twin hispanos (with great ballistics), has good cockpit visibility, it accelerates with the best, and it can even carry 3 250lb bombs... oh yeah, did I mention that it turns well too?

It's only poor categories are range and energy retention.
The Spitfire VIII is almost as good, but because of its slower roll rate, acceleration and top speed it's in a class below the XVI.