Slightly faster, lots blingyer, some real nice refinements like the external adjuster for the trigger and the pressure gauge on the front bottle mount. And let's face it if you buy a speed you will buy the set of 3 volumisers (£38) and a locking gated feed (£30) and a softfaced bolt (£19) all of which come with the A4 so by buying an A4 you really are saving yourself £87 a really good if not terribly convincing argument to give the missus
Get the 4, forget the difference in money, you will love the display, trigger wheeels, smaller size, soft faced bolt, guage, twist lock feed tube, volumisers, but most of all...............IT'S THE DOGS BO##OCKS..................FAST AS F##K.