Hard to give more than general advice from another country, but Dave Atkinson had smaller runs [6 copies] from a UK supplier and I'm sure he would be happy to give general advice that could be very helpful. You can contact him at dave.atkinson27 'at' gmail.com and mention I suggested you talk to him.
My advice from anedotal info. is just don't let a 3rd party do audio remastering for you if possible - do it yourself or leave in original form. Also, try to get a personal [not from an unverifiable source] recommendation for the company you're thinking of using.
Good luck and please let us know how it all went when you've completed the task!