Yep, I went for a post May 2014 model which has the revised 4th gen CREC engine.
2013 saw the 3rd gen DL501 s-tronic, this has the previous issues ironed out.
CREC engine May 2014 onwards has had a lot of updates, see my threads where Dippy posted a link to the Audi information brochure on the updates.
Basically, it use slightly less fuel, revised fueling with an extra set of MPI injectors in the intake, this makes the idle quieter without the clicking of the high pressure direct injectors. These injectors come in at higher revs.
The supercharger is revised with a magnetic clutch so not driven all the time to aid mpg further. But some say when tuning the clutch can be an issue, we will see!!
But looking at the new specs, the drive belt is uprated and higher tensile spec to cope with the SC clutch coming in and out, so it maybe belt slippage rather than clutch slipping. Also has an 'overdemand protection' where the ECU will disengage the clutch if it thinks it has been over used! I'm concerned at how the threshold is set on this!
The supercharger also has revised higher efficiency charge coolers.
Revised timing chains for smoother quieter running
Revised oil cooler
Switchable water pump which doesn't run below 30 degrees to warm the engine quicker - it then switches/pulses on and off to aid cold/hot water mixing more gently.
Revised cylinder liners
Revised oil sump baffle to prevent oil surge under acceleration and braking
Tax is also lower now (same as my old 3.0TDi!!
There is more stuff!
Mine is going into Audi for a recall to check the fuel rail, which one I'm not sure and whether this is just the CREC engine. Dippy has had his from new and not received the recall notice yet, so think it might not be an issue, just more of a check.
But the pre May 2014 engine is still a good engine and possibly better given the 'possible' limits of the supercharger clutch.
I was looking at a 62 plate with dynamic suspension, steering, sport diff, but opted for the newer one and haven't looked back. Maybe when I start pushing it I may regret not having a sport diff, but it drives round bends better than my 3.0tdi sport, and feels quite positive and direct.