Oh yeah, you've also got 3X the heat buildup up in the top of your trunk than with just a single amp. Even with mounting them right-side-up, I'd seriously consider some auxillery cooling (like a few 12V fans).
Cooler = less distortion = better sound
1999 SVT #900/2760 Born on 1-20-99 Silver Frost/Midnight Blue A few aesthetic and audio mods