As Exonian has said
S3 is 310ps
Arteon and Tiguan have 320ps
I think I have read that that the EA888 engine in Arteon and Tiguan are (Evo4) and the S3 is last generation.
They say the engine in Arteon and Tiguan is 320ps (316bhp) and 420Nm (310 lbs ft)
So we wait for all to be revealed for the Golf R.
It would seem to suggest that Golf R will be more powerful than an S3....but that would go against the usual VAG model hierarchy. Also the leaked slide on models (which has thus far been correct) it stated a Golf R with 335ps (330bhp).
I just wonder if we are going to have a standard Golf R model with 310ps (matching S3), but with a performance pack option with 335ps. So price wise, they have something to come in at similar price to S3, but then take some middle-ish ground between S3 & RS3 with a Performance Pack version in low £40ks price point.
I also wonder whether the cold hard light of day and EU fines on emissions, all this talk about a 380-400ps version is dead in the water and the 335ps version is the highest output for a Golf that they will do.