how much negative camber can i get with the stock suspension?

 

You can't.

At least not where it matter's most, the front. Camber cannot be adjusted on the front of the car without purchasing aftermaket adjustble upper arms. Look into SPL, Cusco and EVO350 products.

Do you own a tire pyrometer so you can actually prove what settings are better and avoid unproductive settings? Or are you just hoping to clear a poor tire and wheel choice?

Rear camber can be added, though keep in mind that it alter's toe at the same time, which is also adjustable. I do not know how much rear camber you can have at oem height since I have never had a issue getting the number's I asked to tech to give me. I dont' see why a addtional .5 degree isn't possible IMO, run a search for camber, narrowed to the autocross section and read the post's that come up. Not sure what will come up on the rear however.