Mine too was recalled when it went in for some spray work, unsure exactly what it achieved but it's something to do with the turbo spooling up and looking after it better.
I noticed no difference really in driving but reset my trip computer and have gone from 49.7 to 53.1 mpg over the last few months.
If you can - could you ask them if they know what the upgrade actually does - it would be interesting to find out as I forgot, due to picking mine up from the spray bay which was seperate to the dealers.
Yes mine is the sw, and it was recalled by the dealer by telephone. I have definitely noticed an improvement in the MPG, so far only around town, but hopefully on longer runs it should be even better.