The way the car handles from the factory is nothing short of amazing. It seems like it would be easy to make things worse and hard to make things better. The only thing I would consider to improve handling would be to go to a set of ZL1 1LE wheels and tires.
If you check out these lists you'll notice that the SS 1LE is performing in a league much higher than its price and that most of its competitors use R compound tires.
http://fastestlaps.com/lists/top-grip-kings
http://fastestlaps.com/lists/top-qui...stoppers-60mph