I can't say how fast it will take but I have run 35 quite often without a problem.one thing I noticed is with it wide open you better have goggles on for bugs,ect. When it's partial open you get plenty of air . Do a search on here and you can get a good idea of the pros and cons of the different windshields and doors . Then you can decide on what you want. The buying accessories never ends.just a note most venders on here offer a discount and others have sales quite oftencan you drive fast with it wide open? Is there a speed restriction.