i heard it messes up the structural integrety. but i dont really believe it because its really possible your welding the spots where you cut so your roof doesnt seperate and converables obviously dont have them and there is still plent of lip to keep out the water. obviously if you sit facing the window and spray the water directly at the window its going to leak but keeping the rails isnt going stop that either. just make sure your windows seal well and cut em off in section and weld the roof so it doesnt seperate. and there cant be to much strength difference between rusty rail with bondo and no rails with a welded roof.

just my $0.02

 

shaving your drip rails wont mess up the structural integrety... the drip rails are spot welded in there... and it would look better if you just go in and cut the spot welds out... then there wouldnt be as much welding....

 

I wanted to keep mine so I fiberglassed them. I took off the chrome trim and am just going to paint the smaller area the trim was stuck on to with chrome paint so it looks original. It should still keep water out and not rust with the fiberglass in there.

 

You can do that along the pillars but once you get to the roof it all has to be welded. The roof panel does not end flush, it overlaps onto the drip rail so it has to be cut back and then the entire seam needs welded back up. Here are some pics of mine, not finished yet, they still need filed straight.