Yeah there is an MSY in the city but I don't think it's what you are after. If it's anything like other MSY stores than it's just a counter with a not trained in customer service nerd behind it and all the PC stock will be out back. I'm sure they will serve you fine but there will probably not be enough staff and you will be super conscience about how much time you are taking up due to the angry sighs from the flock of nerds waiting in the queue behind you.
That is OK if you know exactly what bits you want though, right? That has been my MSY experience in Brisbane anyway - walk in with a list of things I want, give the dude the list, wait patiently while he goes out and gets them, pay and leave happily.