Stock tires are 110/70/17 and 140/70/17
There are only 2 tires available in these sizes that are any good (the Diablo Rosso II & Michelin Pilot Street)
I would love to have more options (Michelin Pilot Road 3/4 etc.), but they only come in sizes such as 120/60/17, 120/70/17 and 150/70/17 etc....going up a size in the rear to a 150/60/17 doesn't bother me, but will anything really change with using an upsized 120 in the front? If the tire has to be squeezed on the rim, will the contact patch etc not remain the same?
I would love more stability on the highway but do not want to mess with the handling too much