Is it advisable to replace a rusted Rear Subframe Cradle on an '07 w/94k. My experienced Mechanic will obtain a used one & says it's a 4 hr job. Engine is fine(I replaced Alternator & Radiator), However, Exterior is fair as w/some peeling & flaking as previous owner washed it w/dish detergent eliminating clearcoat. Previous owner also didn't have the melted dash replaced. Car was a gift at 69k

 

If possible post some pics of the chassis. It can be worth it as long as the car is in overall decent shape. What about other components like struts, knuckles, brake dust shields and the like if all that is rotted out it might be time to look for another car. 4+ hours seems a bit excessive, swapping the subframe is quite easy on these cars but he might be factoring in fighting with rusty fasteners.

 

That is supremely rusted. What do the struts look like?

 

The rust and damage will be far worse and more expensive than the initial estimate, then you have to deal with the rust on the front end too because if the rear is that bad, the front must be similar.
A better investment would be to put that money toward a replacement vehicle.

 

There's a high probability that the control arms and other subframe assemblies will also need to be replaced.
In this video, the youtuber didn't replace the other subframe assemblies that were rusted significantly, and it could be a concern.