Actually
@Tashfeen mine is 2.5 years old - went to MRC at the end of Feb 2017.
@Starry - have you had a test drive in a B8 S5? If not I advise it because it is not possible to compare on paper. I haven't driven an S3, but I have driven a TTRS (340PS IIRC) and I'd expect your stage 2 S3 to be similar or even better. You would likely feel that a stock S5 is unexciting in comparison, not only because the lower power and torque, but because it is a heavier car.
Even when stage 2, the characteristics of the 3.0 TFSI are different because of the supercharger. The torque band is broad and relatively flat unlike the peaky torque of your S3's turbo engine. This will be noticeable so you'll want to be sure its what you want. That "shove in the back" feeling of a turbo car when the torque is rapidly rising to its peak is quite exhilarating, and it does not exist with the supercharged engine.
I'm not trying to put you off, just making sure you are aware of the difference. Personally I love the difference because I hated the turbo lag (I came from the 2.7 biturbo of the B5), but I do still remember that "turbo rush" which I got in my S4 that I do not get in my S5.
IMO the gearbox remap is the least beneficial part of the MRC package. I don't often drive in M, so the 'box is usually changing gear before the increased redline. However the torque limit is raised, and although Doug told me that unlike the S3/RS3 s-tronic, he has not seen clutch slip with the B8's OB5, the reputation of that gearbox is such that I'd rather take no chances.
Speaking of which if you are thinking of getting into a B8, have you read up on its problems? In short get one built mid-2014 or later if you can, but if not no more that 1 year earlier in order to get the latest gearbox. If that's not possible then consider a manual, but even then you need to be ready for the timing chain issue, and lesser ones such as the crank pulley and cooling components (pump & stat).