wow you either mis-read or mis-interperted about the quality of amp regarding heatsinks.
Heatsinks are one of the most expensive parts of an amplifer believe it or not. It takes alot of money to machine/cast them. The larger the amp, typically the heavier it is since the heatsink is a chunk of aluminum. A larger surface are heatsink helps insure proper cooling which is better for your amp.
Anyway, judging by the guts, the polk looks to be built a little cleaner and stronger (more caps, stronger power supply). Resale value would probably be better than the profile as well if you decide to sell it later. just my thoughts. I take it you work for circuit city? What are the return repair rates for each of these amps?