Its a shame PE is out of stock on the 800VA since its less than $5 more (if you had room).
I ran mine with 8ohm speakers on 500VA and didn't feel like I ever pushed it too hard. I only moved up to 1000VA because the 500 buzzed and I'm running 4ohm now with unfused ribbons so clipping would be REALLY REALLY bad.
Just a warning, my original Avel buzzed mechanically. Now it did look like the tx slid forward during shipping and bashed the front of the empty case (dented) so it may have loosened some windings, but Avel doesn't necessarily have a great rep with regard to mechanical buzzing.
Plitron is much more $ and slower to ship (built to order), but they seem to have a great reputation. If you go that route you can have it sheilded/screened to minimize RF too.
Here is a quick heads up that may save you some time when you go to wire it all together. To me it seems that the Hypex softstart switch was wired backward. If you use the switch then open contacts is on and closed if off. I wasted a decent chunk of time checking everything else before realizing that it wasn't coming out of standby because I had hardwired the two contacts closed.
