I bought new cowls both sides recently from gmpartsdirect, but only because both sides were missing the rubber part that covers the door hinges (tons of wind noise on the highway from inside the door panels.
All I can say is that if your cowl is fine and just warped, don't go and buy a new one, because it's been about two months since I got them and the passenger side one is already warped.
Just do what I did and take the cowl off, and bend it into shape. Test fit, repeat. Mine is only sealed perfect because I bent it back into shape, twice. Screw these cowls.
I will admit though, the car rides damn quiet with he new cowls
