Does the Polk PSW505 have too much power for my room?

The 505 will definitely not be overpowering in that room. I'd at least step it up to the RW-12d if your budget allows. Even it will not overpower that room. It's easier to turn the gain down on a sub than trying to turn it up on one that will choke in that room.

I agree, that room should easily be able to handle the 505 and something much larger without being overpowering. From what I've experienced, there is really no such thing as a sub overpowering an area....just tone it back if that feeling comes up.

No.

The Polk PSW505 will not work well in that room. The subwoofer is too small for that volume. You really need a good 12" or 15" sub with a lot of power (even the12" might be inadequate).

I'd go with a pair of twelves to smooth room modes. Maybe a pair of tens if the WAF is a concern.

I don't think it's a matter of sounding good or not, I just don't think that you will get a lot of what you're looking for out of it...bass because of the large area you have to fill. I've owned a pair of Bic America F12's.

If you really have to keep your budget down you can only do what you can do. A PSW505 behind the couch for possibly the best results. Add more subs later down the road. RW-12d's would be better though. Add one at a time as your budget allows til you're satisfied.

If you're determined to not go over $300, I think it's your best bet. I haven't had any personal experience with the sub but from reading the threads on it, people seem to like it. You could also go for 2 f-12's but that would put you in the $400 range.

You only need a splitter to run two subs out of the one sub out. The $999 price is bunk. Not any where worth that but a bargain at $300. Not sure how much longer that sale price will last. I'm guessing it will end soon and then be back on sale in a couple weeks or so. Maybe.
Yes, it's worth the extra bucks. I've owned both.

I own the Denon 1613...good receiver. Not too much extra power but has enough to get the job done.

I wouldn't pay that $999 price too much attention. I believe the sub has been discontinued for some time but they are still getting stock from some place and it does go on sale ever so often. Those that buy it feel that it's a great deal at $300 but aren't willing to pay much more than that for it.

I am running dual subs off of the Denon 1613 now. You only need to split the sub out on the receiver with a Y adapter and an additional subwoofer cable which both only cost a few bucks online.

We just like to spend other peoples money.

Stanley, sell me that receiver for cheap.

Buy me a Denon 4520CI and I'll give it to you for free.

Ohhhhh, you're funnnn e.

An oversimplified but still useful equation for matching subs to mains is that the total cabinet size of the subs must be eight times that of the mains, or if the same size the displacement limited power handling of the subs must be four times that of the mains, or there can be a combination of size and power that gives the same overall net result. That's because the longest wavelengths produced by mains are about 10 feet long, those by subs 50 feet long; if a main is a sports car subs are dump trucks. Then there's the matter of room response, which you really can't get uniform using just one sub.