The tires are going to be a little bit wider and about the same height.
the first number (255) is the width of the tread in mm.
the second number (70) is the percentage of sidewall to tread.
the last number (16) is the rim size
I currently have 265/75R16 and my next tires will be 255/70R16's.
If you are looking that is a long lasting, smooth riding tire, but still has a bit of agressiveness, take a look at the Michelin LTX M/S 2's. Thats what my next set is gonna be.