Most people wouldn't know what bumpsteer felt like if it hit them in the head, which it pretty much has to do to make itself evident. What people DO feel, and what a lot of people confuse with bumpsteer, is "tramlining", which is the condition where the car gets pulled around by ruts in the road and uneven pavement. These cars are terrible for it, especially with wider, lower-profile tires installed.
That said, the OP's car would look 100% better if the rear was 3/4 inch lower.