Crazy Idea???

ok, i just thought this up today because they dont make a wheel bigger than an 18 for my wagon. how hard would it be to convert my taurus wagon to mustang rear wheel drive and throw a mustang engine and tranny in it. what i accomplish will be...-good engine-good tranny-RWD(more power)-4 wheel disc brakes-a lug pattern that is more popular than a taurus and 20's are available forDoes this sound nuts or a solution to my problem? the car is already gutted so i wont be hurting anything. LET ME KNOW WHAT YOU THINK.