Intake manifold is plastic...Good reminder. I would really kick myself if I heard it crack.
The two hoses at bottom of intake manifold...I had to replace both of them because they were hard as a rock (one broke on removal, the other broke on reassembly) BUT I never thought of checking whether I broke the plastic neck they fit on to. That is very much the area where the carb cleaner spray gives a reaction. Early on in tracing the leak I thought I didn't have a good seal on one of those hoses so I replaced the spring clip hose clamp with a screw tightening type - now I'll check the plastic neck to see if it is cracked.

I didn't replace the injector O-ring seals so I'm not going there.