Not just your head. The feel is subjective, but every suspension deisign has a limit on how short a sidewall can be before it begins to compromise handling. The advantage of the short sidewall (low aspect ratio) is that the tread is more stable. As your car rolls, the suspension has some variation in the camber built in to compensate for the body roll. A double a-arm suspension has a lot of geometry possibilities. A strut is more limited. As a result, the camber of the wheel/tire assembly tends to track the body roll more than a well designed double a-arm suspension. When the wheel/tire assembly rolls with the body, the sidewalls flex to allow the tread to stay on the pavement. If the sidewall is too short, then the tread follows the camber angle of the wheel too closely, and the effective contact patch becomes much narrower, only using the outer portion of the tire.
One of the misconceptions many people have when putting wider tires on thier car is that the they are putting more rubber on the ground. In fact, they are only cahnging the contact shape. The actual size of the contact patch is determined by the weight on the wheel/tire assembly and air pressure in the tire. The wider tire has to deflect less to go froma round shape to the flat of the pavement. Hence, it is more stable. The shorter sidewall of a +1, +2, etc system does the same thing, it stabilizes the tread on the pavement. To get an idea why stability is important, place your hand on a flat surface and try to slide across the surface. Now do the same thing, flexing your hand slightly. The total contact patch has changed little, but your hand now moves much more easily across the surface.
In answer to your original question, in effect, by putting such a short sidewall on your car, you have had the effect of putting a narrower tire on the car when the car rolls in the corner. Now instead of benefitting from the short stiff sidewall, the tread is flexing as has to go from round to flat over a longer distance. That short stiff sidewall is also transmitting bumps to the wheel much more efficiently.
I have no way of being sure (maybe Luke at tire rack, or other who have had a chance to controlled suspension tests, could shed some light) but I think that given the overall diameter of the wheel/tire assembly, and the strut supension of the contours, I would guess that optimum handling would be with wheels about 17 inches without significant changes in the camber of the suspension.
My $.02
Sorry for the length of the post.
