What you should do is take a pair of tin snips and cut the visor in the middle to make it easier to take out of the window frame.
In channel window visor problems.
That means there s no risk of scratching the glass or interfering with window operation.
The heat will allow the visors to flex into place.
I ve only had in channel visors on my vehicles as i think the outside mounted ones look pretty awful just my opinion but i ve never had any problems with the power windows not operating properly.
No window contact also because of their out of window design tape on deflectors don t make any contact with the glass or window mechanics.
In channel vent visors do not have this benefit.
Obviuosly the first time you put them on and roll up the window it ll be a tight fit but that s what helps them seal.
Quick discussion on installation of in channel versus exterior auto vent shade window visors.
Also you will need to tug outward on the visor when you roll the window up the first few times or the window will catch on the edge of the visor and possibly break.
Obviously do this with the windows all the way down.
In both cases no drilling is.