Much like the 350z Andy. Only with them moving the strut brace under the floor rather than over, there is less space in the boot compartment compared to the 350z, whereas there is probably a little more under the carpet.
Underneath the carpet IRRC there is the amp for BOSE - but now infront of the strut and not in the corner like the 350z. The BOSE sub is designed to fit in a spare wheel (which is missing and replaced with foam), loads of other foam and tyre inflator and thats about it. So loads of room to make some compartments to stash stuff.
If you dig around there was a recent thread where a member had the BOSE sub removed I think and he replaced it with a neat lower boot compartment.