Now Cooper S or later Cooper SD !?

Hello, the Mini Cooper has managed to get into the short selection of a new car. I would even say that the decision is 90%!! Now I ask myself the following question: Should I now (December) opt for the Cooper S or should I rather wait a bit and then take the Cooper SD? At the moment I drive a 118d and am actually satisfied with the performance. Compared to the 120i (170ps) I would definitely prefer the 143 HP diesel. Wouldn’t the Cooper S be much faster than a 120i on the road?