All components are suttered/suddered (Sorry, not a native speaker) onto the motherboard, it's not possible to upgrade any part
I'm not entirely sure about storage yet however.
And using an i3 would cause serious issues, if it were possible to use it that is.
Since the Atom Z3740 1.33GHz processor that is in my Asus T100TA is using 2W only, using a CPU like Intel Core i3 would use at least 30+W (More than 2W) which means you'd have battery problems with your laptop, if you want to have a faster notebook I'd suggest cleaning up your Windows.