Is this not a money isue only? 
Will the CS be better and faster than the R in some point?. I know the CS used to be the better trackcar...But that seems not be the case now?!..
Or?... 
But the CS is a awesome bangs for buck!, and have the best interior seats!!
The money difference isn’t huge aside from the fact you need to spend a lot on extras for the R to make it the car you’d want it to be.
Fastest when the speed limit is 70mph is a little irrelevant in the UK.

I’m sure with torque vectoring on the rear the R will be quicker round a track if that’s your thing.
With drift mode it’ll be great for the late night car park crew.
And from the traffic lights the R will always be top dog by a big margin.
So 3/3 for the R.
Trouble is not everyone wants the range topper just because it has the best spec sheet and the most exhaust tips.
How about most fun at sensible fairly legal speeds and a modicum of skill needed to drive it?
Maybe the 8R will win that one too, I for sure have no idea.
In fact at those speeds I’m sure the regular 245 GTI would be just as good.
Not everyone *wants* an R
Personally I think if you want a Clubsport you ought to keep the spec fairly simple (it’s hardly lacking as standard) because once you get into R money then you really need to ask yourself the question.