firewall insulation on a 35 coupe

[35 coupe]

Wondering if anybody ever bought firewall insulation, the one with the plastic and have any trouble with it, the holes being off space, top to short etc. It seems that when new parts don't fit on your car, they tell you that they never had any problems in the past with that part, or they tell you there must be something different about your car, even if it is stock, and it cost you extra to send it back, so the money you saved by buying from different vendors goes out the window.