Hey! I just did ED with my Z4 M40i back in July. I had zero issues with trunk space. I was able to fit a large eastpak suitcase into the slightly tighter portion of the trunk at its deepest point (this one:
https://www.eastpak.com/uk-en/luggag...9X+00+999.html), along with 2 backpacks, and other small items as well. Could have fit more into the trunk if necessary, like a duffel bag. It's surprisingly roomy back there, given the dimensions of the car. The netted portion behind the seats was perfect for water bottles, snacks, and baseball caps. The small passthrough cubby can also hold baseball caps or other similar-sized items without an issue.