Loads of room, you just need to be creative! Plenty of room for squishy bags behind the seats, and relocate the alarm sounder (10min job) and you can use the frunk too once you turn the spare upside down. We used to take ours away for camping weekends, great fun
Would def go for the MX5 though if you have a lot of stuff to take. Just be aware, the boot isn't that big...