Take a normal toolkit with you and you should be OK. But don't forget to take your small brushes and air blower along as well!

When you opened the unit last time, was it clean inside, or full of fluff?
But be aware of that if you open the board cage covers you need a password to enable Service Access. Removing these covers without the password will (probably) cause the system to be disabled! A brilliant "feature", or what! However, the
good news is that simply opening the fan tray and plastic side covers should not cause a problem!