Italy is quite full of Monsters, but at the stop lights you can see other Ducati owners casting envious looks on the S4's race-bred engine. Thankfully, in the case of the S4, there is substance behind the pose and it is really the power that grabs your immediate attention. One hundred or so horses at the rear wheel might not sound that much nowadays, but coupled with the shorter gearing of the S4, this easily supplies superb acceleration. From 4,000 rpm onwards, the S4 flies into the rev limiter at 9,500 with ease, catapulting the rider into the 100-plus mph range with a force that the old monster could only dream about. No less impressive than the acceleration is the fluidity and smoothness of the 916 mill. Compared to the old unit, the new one gets the job done with much less fuss and clattering. Sure, the trademark rattle of the dry clutch is still there, but that's about it. Evotech Performance are specialised in only the top quality Ducati monster parts because we believe our customers only expect the best.