Did some research on back spacing using: http://www.autolounge.net/calculators/tirespacing.html
Stock 15x7s have 4.5 bs, so +12.7 offset, so that gives them 3.5 front spacing..
Those 15x8s have 5.5 bs, so +25.3 offset, so that gives them 3.5 front spacing..
So they would stick out the same as stock but have an extra 1" of rim sticking in..
makes me wish I had my stock spindles on to do a mock up..
I do not see any problems with the sway bar.. but the tie rod end looks like it could be a problem..
I would run 235/60r15s which are a tad wider than stock, but not by much..
Is the problem with the rim, or the tires rubbing? cause the 31"s are not going on them..
other similar style rims to prostars: torqlite, jegs sport star, summit star wheels, or cragar 641.. though the prostars use a different type of lug nut..