#1, some members here pointed out that it's caused by old firmware. Maybe the installer didn't make it update for you (some people here kena, installer just plug in box, activate then leave. Some never activate at all, had to call Astro and complain). See if you can get the box to update by putting it on standby for a while. To be doubly sure, unplug box from power for a while, plug power back in, then don't touch it, let it show clock. Should automatically start update after a while.
#2, I don't think so. I stack a VGA box on top of my decoder and it's still quite cool. On the other hand, my box is somewhat "suspended in mid-air", underneath has nothing blocking the vents because just two steel support bars of the table is holding it up with the vents unobstructed.
I think they get better reception because they're on higher ground than us, even Temerloh.