screw removal

I’m trying my damndest to get these two tailgate screws out to install a flag holder (go Leafs) I’m using Liquid Wrench, an impact screwdriver (T40) and a torch to heat. It’s about -4°C / 25°F where I am so I’ve been holding the heat to it longer than what I’ve read is suggested, but they’re...

I’m installing a new sub but it’s been a pain trying to get it to sit correctly without seeing it/being able to adjust it. I have the proper triangle bit for the 4 triangular screws that are under the unit cover. I’m wondering if it’s even possible to remove these. It looks like the ends of...