In the US, on the 17" wheels found on the Sport and the Touring models, they use the Yokohama Geolandar tires. Which have a lower PSI recommendation.
Sorry it took me a while to reply. The 17" alloys in the UK are also on Yokahama Geolanders (factory supplied on the SE and SE-L). I have a set I'm going to fit to compare the ride quality of the 19's on my Sport Nav (I like soft and comfy). The pressures are indeed lower on the 17's, as per my earlier post