I made my own out of angle iron and longer bolts needed and painted black. Worked out great.I did a 3" lift to get a pair of tens under one my 98 3 doors in 2000. Passengers still rode just fine
i was thinking of a way to do that with the rear seats in my sentra, to maybe put some 8's right under the front of the seat without losing leg room. not that i have people in the back. even thought of ditching the tear seat all together