Installed the spacers today. They lift the seat up
Just enough for proper clearance.
Now, I have full motion of the reclining seats, although it is not smooth as the seats still rest on the box. I can recline while seated, but it takes a bit of effort and the box will sometimes slide forward with me.
Be aware that raising the seats throws off the geometry slightly of the latch mechanism. If you have the recline in the full, upright position, you cannot latch the seat back if it was unlatched. You have to recline forward completely to latch the seatback. Once latched, you can go back to full upright recline, but you can tell there is pressure on the latch that doesn't want to the seats to go all the way back.
I hope I explained it well enough.
Overall, I love the box. The sound is great, though I may add some polyfill to it to bring the box volume closer to the subs recommendation. I'm using JL 10W0v3.
I am disappointed that I had to add spacers. I bought the 10" version because the 12" required spacers and I didn't want to go down that road...it was not clear up front that spacers would be required. I had 2 12" subs already....
The experience from Fox Acoustics was not great. Lack of communication on the spacers and relatively slow shipping are my gripes. Joe Fox responded quickly to my emails and had a tracking number for the spacers I needed that day, though they didn't actually ship them until 2 days later.
I was surprised that Joe asked to use my pics for his site, though he hasn't posted them yet.
I hope this helps someone and made sense. Having a few celebration brews!