The place for Republicans to make their voices heard is primary election. Republicans who choose to "sit out" a general election have still made a choice...and a silly one at that. Conservatives who don't vote in general elections are out of their minds and hurt our party.
SurveyUSA does a fairly decent job with their polling. This interactive is entertaining, at least, in predicting the outcome. You can set the pairs and see how they think it might turn out.
http://www.surveyusa.com/