....
The reason why i want to change them is that they are not straight at the top meaning they won't seal properly with the door leading to huge wind noise.
Eric,
even the original door windows are NOT straight on top! The front and rear end edges are lower than the middle; see photo.
The front-rear tilt can be adjusted two ways. (a) the glass can be tilted a bit as shown in the third panel and (b) the complete scissor lifting structure can be tilted as shown in the bottom panel.
If your mechanic has never done a window adjustement he may be in for some frustrating hours. In addition to the front/aft glass tilting as described there is a critical in/out tilt, that is, on a closed window the top must meet the upper horizontal seal groove and that is achieved by adjusting the front and rear bolts of the window tracks at the bottom of the door.
First time to do this can take a week!
Also ".... sub par US made replica side windows that are not even identical in size and shape"...
No matter how hard and long he'll search the left and right window are never identical.
I very much doubt that this is a window problem.