They aren't all that bad. I replaced all 3 in my smart several years ago. The hardest part of the rear two is getting the air filter box out so you can get the the one over the transmission. Once that is out, simply jack up that side of the motor to take the weight off of it, and remove the three bolts holding the mount assembly to the trans, and the two on the body, and pull it out. Replace in reverse order.
You do need a set of e-torx sockets, because virtually the entire car is assembled with those...
Rock Auto lists the Front Mount as a "Torque Strut Mount" and the other two as just "Motor Mounts" in the "Engine" Category.
I've only changed the front motor mount, but that required a Torx E18 socket. Cheapest E18 socket near me was Harbor Freight's Torx E Socket kit but it's definitely possible to get it cheaper if you want to wait for shipping. I actually flipped one of the bolts so I could get to it easier for the reinstall.