There are two different gas tanks in first gen runners. The 17 gal tank hangs down about 4 inches below the frame, and the 14 gal tank hangs down about two inches. I guess the 17 gal is the SR5 tank but I'm not sure, I know my 87 is an SR5 with the 17.
The skid plate really adds to the rock anchor aspect, if you take it off it really cleans it up. The tanks are fairly durable, lots of guys dent the crap out of them until they lose capacity, apparently without issue.
