could i drop the 3L into a 4 cyl contour mtx? - yes....if you got lots of $$$ to spend
would the trannys match up? - no...you need a v6 tranny, teh bellhousing is different
you would need the v6 subframe, computer, wiring harness, and loads of other stuff. much cheaper to find a v6 with a blown engine for cheap, sell your car, and replace the blown v6 with a 3L