Diesels of the late have been impressive. In fact I was looking at 123d before I got into a Clio. By no means the twin blower is slow, and its more than 200kg heavier than the 200.
With diesel you can't just look at hp as most of it is coming out of the low rev range, plus it pulls much better than petrol. It's prob a better everyday car.
On straight there's not a lot of diff between the twin blower and 200. It really comes down to handling, and you do need a DSG to get the diesel drives properly.
... but then, of course, being Beemer $$$ is an issue.
Don't forget you have Cupra R in diesel.