Since I have 2 Labs that I regularly haul around, my rear compartment has to be absent of anything chewable... even the seatbelts are removed. Since the rear compartment where the factory tool kit was a little small for what tools I wanted to include... I was trying to come up with an area to store a little bit bigger tool kit... Without a need for a 2nd battery yet, but wanting to someday do that mod, I thought it would make a decent location for a little extra storage out of the way... so I ordered the washer bottle relocation kit from Slee and the 2nd battery tray kit from Cdan and I now have a tool bag compartment where the dual battery would go. A little warm, but as long as you don't store WD-40 or other compressed fluids, it should be ok: I am sure someone else has thought about this, but couldn't find anything in search: Roughly 12.5" wide X 7" deep X 9" tall to clear the hood. The only nice tool bag I could find that just fit these dimensions was this Bucket Boss Gate Mouth Jr I found at Sears. Fits nice and holds plenty for what I would want to attempt to fix on the road. Probably could be used to keep take-out food warm on the way home also!