So the driver is in the box and I ran a few tests. I didn't detect any leaks, but two screws are only about halfway in because the glue for the inserts hasn't dried yet and I didn't want to force them in and knock the inserts loose. So it's a little leaky, but not from any of the seams, which is good.
Here's what it looks like from 1m away. Blue is the raw response, red is with a boost right around the roll off point and black is with both the boost and with a little EQ applied. Excluding that dip right at 39hz I'm about +-3db from 17hz to 200hz and with the dip I'm +~3 -~9.