Not really hard at all. Put the front of the car up on jack stands on the frame rails. Once it's up, use the jack to lift the engine ever so slightly, there's a flat spot kinda towards the driver's side. It just helps to take some of the pressure off the bolts. Towards the rear, you'll have to bend or cut the little inner tabs off where the stock mount sits, otherwise the AWR one won't fit. I just used a Dremel tool with a cutoff wheel and took the tabs off, others have bent them out of the way. Slide the new mount in place, replace the bolts, and that's it.
A good socket set with a breaker bar works wonders.
This is just for the rear mount, I haven't put a front one in yet.