I've had my ST3 for 2 years and 3 months and have done just under 16,000 miles.
My daily work commute is ~18miles each way with mixed 30/40/50/60mph A roads and I've accurately calculated 41mpg over the total mileage (trip computer is reset on each full tank and the readout on it is 45.1mpg as of yesterday). I've only used premium fuel, mostly Shell V-Power (30 tanks), Esso premium (14 times, mostly full tanks with a few top-ups) and 1 tank of Tesco Momentum 99 (which gave me a noticeable drop in power/mpg).
I have some ST car mats but can't honestly remember if they came with the car or if I bought them online (haven't actually used them as I kept my previous Zetec mats which are still going strong).
I'm still on the original Bridgestone Potenza's which at my last service at the end of March had ~6mm rear and ~4mm front.
Unfortunately I've slightly kerbed both passenger front and rear alloys within 6 months of getting the car (both times when attending medical appointments so I must be cursed when doing so ). I didn't take out the dealer insurance cover though I should have sorted out some kind of third party cover which would have been better value. Still, since kerbing them, there has been no more damage so I will get them sorted out before deciding on either keeping or returning the car next March.
Last but not least, the oil for the Ecoboost petrol engines (including ST) is 5w-20 though 5w-30 is also listed in the handbooks. I picked up 5L of Castrol Magnatec Professional 5w-20 for £28 before my service and it knocked £100 off the cost!