^^So handling with the 19's is better than the stock 17's?
And you downgraded the rears to 235's from the stock 245's along with the 8" wheel from the 8 1/2" stock wheel.

 

19's do not handle better on this car. i ran 225/35-19 and 255/30-19 on 19X8/19x8.5 and it absolutely handles like garbage. It was fine on the street (not better) but way worse at the track.

Non-staggered (if you go wide enough) can improve turn-in and front in grip but you also increase oversteer. I think to see the full benefits of non-staggered you need to run 255's all around minimum.

 

Anyone got pics of running 17x9 +45 with 255's all round?