Hi i have had aero screens on my cobra for a while and enjoyed the experiance. i made them my self making a base out of alloy and fibreglass then rivited some 1.6 mm polycarb to the base.
the only thing i would change is to used an optical quiality polycarb as i found it a bit hard to see thru at night.
You will need to put one on the passenger side as well or you will be doing a lot of driving on your own.
how well it works depends a lot on your seating position as i sit very low in my car i had no wind issues with the aero screen. other than you do get wet if it rains i have been up to 120 kph with it and had no problems with flex or vibration.
another tip for you is when you mount it you use the demister vent holes to bolt it down as when you want to put a normal screen in you dont have any holes to fill in.
I have attached a pic even had no problems with my cap.
oz