BAT POLL...

Going from 350Wpc to 550WPC will give you about 2dB more power. I doubt that it would make a significant difference in listenable output unless you have your 801s in a huge room. You might want to add the BAT-PAKs if you don't already have them in. That would make a much bigger audible improvement.

Or if you want to step to another level go to a Jeff Rowland model 8T, is the maximum level of all the traits you described.

I can't imagine the VK 1000 Monos not giving you the feeling of "enough power"...BTW, the BATPAK option is standard on the 1000's. Something new you might check out is still in the BAT family, the VK 6200, a multichannel amp that you can have outfitted with four mono amp modules and you could power bi-amp with one 4 channel amp. In some ways it outperforms the VK 500 ( 2 channel Vs 2 channel), since the 1000's are really two 500's strapped, you might want to experiment. The VK 6200 in a 4 channel configuration lists for 7500.00

Kind of guessing as to what your dissatisfaction might be with the 1000's. If it is bass problems, my experience is that the N801's can easily overwhelm even a 5000 cubic foot room. No amp will be able to compensate for too small a room for these speakers.

Another option you might want to try is putting BAT's tube products (150SE is their monoblock version) on the mids/tweeters. Have heard their tube/upper, ss/bass demoed on other speakers and enjoyed the combo immensely.

Pcc, give the BAT factory a call on your question. Both Steve and Victor are very easy and willing to answer questions. I suspect yours has been asked before. Might be a nice additional product for them.

If your looking for more power lincoln makes some great arc welders which is pretty much what you would need! Is there any way you could bi-amp your speakers with 4 VK-1000 and if you can I don't want to see your electric bill! Good Luck.