Granted any downforce is going to lower my top speed, but I'll counter that with other mods I guess. My main concern is stability up there in the 160-180 range. Does the Z06 spoiler really help at all? That would be the first step I guess. A chin spoiler I am sure would help too, but I can't get over speed bumps as it is. Do they make any that don't lower the car much, but actually increase downforce?