IS this Safe or worth doing???!!???

If coustoms truck BLUE HELL featured in the Dec Truckin mag layed on 24's i got to readeing and notice they had the wheels Milled down to get them to tuck on the front and the rearend was narrowed 41/2 to tuck. the wheels i am runnin on my zu i love and dont wanna change so was wondering if this is a costly mod or if it can even be done on my truck if so would i just go to a machice shop