I made this an hour before driving 36 hours from Southern Ontario to Central Alberta. Took about 15 minutes using scrap steel left and 2 21mm head nut and bolts left over from replacing the front control arm bushings on my sisters Cobalt. One 2x6 strip of half inch steel welded horizontally with two plug welds to spread the load over the thin bumper metal and then one 2x3 strip welded vertically on each side. Already had all the bolt holes perfectly sized when they came out of my scrap bucket and tack welded the bolt heads. All I did was clean, prep, weld and paint. I put a roll of hockey tape on the handle and zip tied it to keep it from rattling.
I would recomend the hi-lift blanket/case thing because being on the front after a long winter trip like that took it's toll and it would not ratchet until being cleaned and lubricated. Damn Michigan and Illinois salty roads.
I would and do keep mine inside so it stays clean and functioning properly. Just remember you will most likly not be in the best mood looking for the hi lift. Putting the hi lift in a place thats a pita to get, needing to move everything, pisses me off.
Wherever you put it make sure you can get to it even if you are loaded down and secure it in a way that it doesnt take 10 to unbolt
Probably wont work on a 4 door, but I liked mine here. Always easy to access, was mounted nice and tight. It scraped against rocks from time to time, but never really got in the way with the tire sticking out further than the jack.
Only downside was dirt and whatnot. I took inside for the winters so new england salt wouldnt eat away at it.
I like the mount under the back seat. I saw it today on another post/site and it looks like thats where it is supposed to go. All the carpet is removed and it slides right under the existing kickplate to the backseat, then stabilized with screws.