Originally Posted by OldRice

So I offer this suggestion for bottle placement. Mind you I have a 350Z so I am not sure if Nissan carried the same trunk features to the 370 and could not tell in your earlier gutted pics. In the spare wheel well on 350's there used to be a weird shaped cardboard like piece that lays across the spare under your trunk mat. Under all that there used to be a threaded mounting hole in the middle of the trunk\hatch area that is used for a screw fastner to hold the spare in place. What I did was to remove all those pieces (weigh savings from the spare). I then used the odd shaped carpet mat as a template that I transposed over to some 1/2" pink foam insulation board (avail @ hardware stores) to create a mock trunk floor that lays atop the rear interior wheel well trim pieces and bridges the "gap" where your spare was. Once trimmed and fitted, I transposed the foam board shape to 1/2" MDF. Then drilled a center hole in the MDF in vertical alignment to the factory threaded mounting hole for the spare.

Then I used this bottle bracket type (see attch pic). It come with predrilled holes. I widened the center hole on the plate and bought a 7" long hex screw. Put in your dummy mdf floor, center your bottle bracket plate hole, run the long hex screw to the spare mounting hole, and tighten the the whole thing down. It all holds together with compression, avoids having to drill the trunk floor and dropping the gas tank, and you can revert to stock without permanent alteration. Carpet the MDF and you have that pro-look. My avatar is the finished look. Hopefully my concept is clearly explained.

...then do the hide-a-gym-bag thing if stealth is important.