Just remember whatever you engineer to lift the car shell up to install the engine package also may need to support the weight of the assembled front end when you are through. It may have to hold of lift the weight of the complete front end to remove the engine cradle to get the car on stands or the tires. Same for the engine/x-member cradle. You need to design the cradle or the body lift brackets to handle the total weight of the mated package, not just the weight of the single pieces.