I had ran Axe Rossi engines the last season and I'm now breaking in one Cobra X1 and one Mamba X1 for the next season.
The Evolutions X1's have some issues fixed and are ballistic.
I have 1.5Gal trough my Cobra X1 and i never ever saw an OS Speed rev as high as my Cobra X1. In fact i never saw and engine perform that kind of top end! Bottom end is also better than the Speed and C6BB7T engines. This new Axe engines will shake the 1/8TT world.