KRELL FPB 650M MONO BLOCKS ..?

Hi..
I'm currently using a pair of krell fpb 350m (mono blocks) to run my B&W 801N. I would like more power for my pair of B&W 801N. And I have located a pair of krell fpb 650m (mono blocks) near by and is available for me to purchase. I would like to know will that be a great upgrade for my pair of B&W 801N. Any advice and opinion will help.

Thanks

mac