griffin, I have an 805 as a preamp, and I also have PSB speakers.
I think you'll be fine as long as your volumes are moderate. Depending on what kind of levels you want, and how far you sit from the speakers, you might be just fine.
Just use your ears. If it EVER sounds like there is straining, turn it down. OTOH, if it sounds great as it is, well, there ya go.
The 805 has a very beefy mch amp section for a receiver. You couldn't find anything stronger, I believe, for the money spent.