I have read all the threads here but want feedback on what I have researched.

The AP1 comes with S-02 in the following size specs:

on the stock size of 6.5 inches (+55 offset)
205x55x16
sectional width 8.1"
tread width 7.1"
height 25"
revs per mile 833

on the stock wheel size of 7.5 inches (+65 offset)
225x50x16
sectional width 9.2"
tread width 8.5"
height 24.8"
revs per mile 840

Note that while the tire size should indicate the diameter would be the same in fact the tire specification is not the same, the rears are shorter.

I have BBS rims the are 17x7.5 +48 and 17x8.5 +55. I am presently running Michelin PS2 in the following sizes but am considering replacing them with Michelin Super Sports which seem to be a perfect match regarding the height specifications

225/45ZR17
22 lbs.
rim width 7.5"
sectional width 8.9"
tread width 8.2"
height 25"
revs per mile 833

245/40ZR17
23 lbs.
rim width 8.5"
sectional width 9.8"
tread width 8.5"
height 24.7"
revs per mile 841

QUESTION is while the stock tread width is 7.1 / 8.5 20% wider on rear the new tires are 8.2 / 8.5 which is only 4% wider on the rear. I know the larger 17inch may affect this calculation still it seems the new setup is closer to square the the stock stagger. What will the resutls be? More oversteer or understeer?

The SuperSports are not available in a in a 255x40x17. After readng several threads it seems the Dunlop Z1 Star Spec are recommended and offer the 255 size. However while the specifications match up they weight 26 lbs each for both the 225 and 245 which is considerably more than the Super Sports which are 22/23. The difference seems extreme for same size tires. All the specs quoted are found on tirerack btw.

 

We get the specs directly from Michelin so I would hope they are correct. With the wheel you have the 255/40R17 will fit but may need more negative camber or a small fender lip roll. The 245/40R17 should fit with no issues.
If I can help let me know.