yup. He was running a 3k to each, now with the 8k the pair. But, he's pushing 6400W to them.
I'll have the 3K on my subs (dynos at 5k dynamic power at 1ohm) that are rated at 1125 each.
It's not a bad thing to have more power on tap if you are going for SQ as well. An amps distortion goes up as it reaches it's power limits, so if you are only using half the rated power you will have a cleaner signal. A lot of competitors will have 200W on their mids and tweets, but only actually use a few for the tweets and 10w for the mids.
Power doesn't kill speakers, distortion does by creating heat, or exceeding a speakers limits, on a sub that would be bottoming out the voice coil/exceeding the excursion limits.
So if you see a deal on an amp with more power (not necessarily my brothers) pick it up, it's not really going to hurt anything if done properly.
Side note, you will see output gains from ported vs. sealed, but the box will be bigger, sealed should play more even and lower (depending on the tuning of the ported enclosure). So if you strictly want SQ, sealed is probably better.