The 1.8SR has straight line superiority between 30-70mph. Off the mark they are no different as the TS is much lighter, however the torque bonus from the bigger engine will have the 1.8 inching in front. However its nowhere near as "chuckable" as the TS which you can launch into roundabouts and tight bends and come out with a smile, while the 1.8SR will have you wondering if the steering wheel is actually connected to the front wheels. In short... the SR is slightly quicker in a straight line, but the TS will obliterate it round the bends. Also the SR ofcourse only has the US market derived 1.8 with about 140bhp, some TS's in the past have had straight forward mods and produced the same power. Couple with a decent set of coilovers and you have a very nippy and fun gokart like car.