If your appraised value is $175,000 then you would be able to refi up to $183,750-you would need to come up with $10,000 plus closing costs. This is, assuming your loan is held by Fannie Mae.
If your loan is currently owned by Freddie Mac, then you might be able to Refi without bringing any money to the table at all because they allow up to 125% in certain situation.
I have provided a link below so you can check if Freddie Mac currently has your loan.
Your credit is phenominal! It is very rare for someone to have a middle score over 810.
If you are able to do it, you can significantly reduce your rate. As far as should you do it you can contact me anytime to discuss (I am available on Sunday) at 908-415-3958.