I know the class A/B amps are known to get a bit warm and even hot! After I installed it on Monday I drove around for an hour and really hammered on it. The subs were singing pretty much most of the time. Temperature was around 75 deg that day. It was slightly warm to the touch when I stopped. Not hot at all like I was expecting.
Yes, there is no active cooling but the heat sink is pretty huge as you can see. Also there are gaps underneath the amp as well. It isn't captured well in the picture. I'm hoping that all the surrounding airspace on top and bottom of the amp will fare well when it heats up more this summer.
To me AB amps are the coolest running. Class A are insanely hot and many amps I used were tube amps so 500-600F bulb temps were common. But yeah, AB1 and AB2 are hot compared to a class D amp.
I think your biggest issue may be on either really hot (90-100F) days or really long trips. As the air around the amp increases in temp it really has no way of escaping that area, its trapped.
IF you do run into an issue, cutting slots in the edges of the cover near the sides may help greatly. Since the sides are what support it, maybe front near the seats and back near the hatch would work. Something maybe an inch wide by almost the whole length of the cover would probably do wonders. Whatever will allow a draft through the area without looking butt ugly is your best bet.
But i'd do what you're doing for now, just wait and see what happens.
