It's a personal opinion but I didn't like the (new model) S3 I had on test a few months back and despite all the ponies I don't believe I'll like the RS3 version.
I'm an interiors person - after all, that's where you spend all the time, so it's a good idea to love the driving environment. It should be, at the same time, engaging yet focussed. You shouldn't have to deal with (i.e. think hard about) anything beyond what's in front or in your mirrors. All your tools should be available by touch (once learned) with minimal visual input. The new layout is so messy it's difficult to believe a car designer had any hand in it.
I'm happy with where things are in the current version, I've always liked a good well thought out layout, with nice switches and things (goes back to my Jaguar days) and from my first Audi (starship A8 4.2q) always had a great layout that once learned you could fit into pretty much any Audi and just drive off knowing stuff was where it should be.
Then they go and spoil all those years of attention to detail, care and consideration and put a loathsome little plastic temperature thing in the middle of the car (as well as that damned screen on the dash). I'm sure the cupholder is going to be very handy too. All those new things to learn - and read in tiny wee red letters which are as useful as a chocolate teapot. Particularly to the slightly visually challenged - I don't want to have to put my reading glasses on to see what's happening. (Sad but true)
In engineering terms when it doesn't look right - it ain't right, and this pile of poo ain't right.
Then we get to the outside. The current RS3 is fairly angular but has its nice curves too. The new one looks like it's going to cut something with all those angles. I haven't taken to the new shape A3 at all. Good grief, even the saloon (aka Jetta) looks good by comparison.
It'll probably sell like hot cakes but it's not for me. Nuff said.