Hi,
Welcome to Retrobike!
Hope you've already been warned about the danger to bank balance/kids dinner money fund/family relationships that generally starts here.Hope the experience is a great one.Personally have found loads of help/information/spares etc.Great bunch of people.
Is that STX/STX RC?Just out of interest,do you have a faulty shifter you need to replace?There's a common fix for sticking Shimano shifters if that's your issue?