Yep, agree with Doc on the potential engine output - probably closer to 420ps which is getting towards the boundaries of the existing turbo (from Audi's warranty point of view anyway)
There are some road tests for the new TTRS starting to appear on Youtube (see link below - good detail on the new stuff) which gives us an insight as to new parts which may possibly put in an appearance on any facelift/product improvement/new model for an RS3 Sportback.
So what might we see....
First there's the obvious potential of the new engine with it's upgraded technology and alloy bits (26kg lighter and producing an Audi quoted 400ps), then we have some nice carbon ceramic brakes, expensive but wouldn't it be nice to at least have it as an option on the RS3.
The virtual cockpit (which I tried out for the first time earlier this week and was surprisingly impressed), the dynamic lights with OLED technology - again I suspect all of which will be options, and then also some changes to the Haldex system which I think will be torque vectoring technology.
In addition to the above, there's the cosmetic changes to the front and back including a new grill (similar to the recent A3 facelift)
I guess all this will jack the price up of a TTRS, but would also do the same for any of these parts that MAY also migrate to a new RS3.
If any of the above new parts end up being specced for an updated RS3 Sportback, then I can't really see it being a facelift, but in fact a new model...of which I would be surprised if you could get one on your drive much before 2018!!!
Back on topic... I actually think the new TTRS looks good with the new aggressive looking front end, I even like the Nardo coloured Roadster too! Combine that with the 400ps engine and that 5 cylinder soundtrack - Audi probably wont be able to keep up with demand.