Installed them only on 1 vehicle so my info is a little limited. I mounted them on lowest corner of the door. I honestly used a kit that had the 30's for this project and they worked just fine for that project.
It's all going to come down to weight of the door. This was mounted in a standard 2 seater door with T-tops with stock speakers. Anything added to the door (heavier speakers), body molding and you have to consider stepping it up but not by much. If you go to much it almost pushed the doors out and will make a noticable annoying thud. 30's were subtle and did the job well. Haven't checked up on the project but last time I checked, he loved em.
