I own a Mazda6 TS2 58 plate. Its the 2.0ltr TD model. It has not put a step wrong on me, drivers very nice and its really comfortable on longer drives. I bought mine for £6700 with 54k on the clock about 9 months ago. I have already done 20k in its still going great.
If I had to grumble about something, I would say that the suspension is a little rolly. I am used to sportier cars like Accord Type Rs, but once you get used to it its actually very predictable in the corners.
I don't know if any of the above is going to help but if you have any questions just ask away.