i just check yesterday, and sony even have 50% off on warranty, too!

if you use normal wireless mouse, you will need to plug in a usb receiver for the mouse. if you have BT build in and have BT mouse, you don't need the usb receiver. it is not too expensive to get BT built in (around USD$70) but you can't upgrade it yourself later. however, sony BT can connect with everything except BT headphone.

you can add ram yourself. it is very easy to do on S-series.

when i do things with my computer, i usually put on rubber gloves (those used by hospital) so that my fingerprints won't be all over the place. something you can consider if you really "baby" your new machine.