Surprisingly there's only about 20 kgs difference between the weight of a duratec and sigma engine, and the spare wheel and rear rack (about 20 to 25k ) would add considerably to the 4/4 rear weight bias, so not quite as pure.
Without question my 2012 Plus 4 sport was the best handling trad, I have enjoyed, so I like the sport versions as long as they haven't added lots of weight to dilute the purity. Nice cars.