You can literally run 120 MPH with one of these on. I had one for years. Things to consider though. You have to remove it at least once a week...because if you don't, It will start eating your paint (rusting). The other con is that it will magnatize your cowl area, so if you are doing a repaint anytime soon, It could cause paint issues when your cowl area gets sprayed.. Those are the only cons. Does it keep out the water? Absoulutely!
Much better than those Plastic Metal knobbed covers if you ask me.
Melbourne, FL (Formerly from Long Island, NY!)
1965 Mustang Convertible 200cid I6, 3spd Manual
1966 Mustang Sprint 200 Registry Owner/Moderator
1966 Mustang Sprint 200 Convertible 200cid I6, C4 Auto
2007 Mustang V6 Convertible w/ Pony Package