Well, i havn't had any experience with polk radios but, i do hear they are a pretty good radio. Well the questions with the servos you are going to get many differant responses. This plane doesn't require huge high torque servos. I myself am using futabas 3010 servos on the rudder and elevator whcih gives me .20 seconds / 72 ounces of torque at 4.8v. Personally I think this servo is more than capable of flying this model. The more expensive 92 series servos offer the coreless motors which are very nice; does gives you more persision and speed but then again you are spending the extra money. Of course this bird does love to be thrown around the sky and if you are going to really push it to the limits you could probally use the better 92 series servos. On the ailerons I did use futaba's standard BB 3004 servos but, have replaced those with the 3010's as well for more crisp roll authority.
You are going to enjoy the plane; as for when i get a chance to fly it i do enjoy it greatly.