picked up an 06 equinox with 140k miles. good tires, even wear and inflated to spec. on short test drives as i just got done fixing the headgaskets i notice a somewhat odd “poing” sort of sound from front suspension on road bumps. not a thud or bang but a sort of not right sound. probably will turn into a just starting to wear out front end parts and check everything that might wear? struts? sway bar links? bushings? control arms? even going over expansion strips results in kind of a ping/poing sound. almost like having the tires vastly overinflated. maybe its a bad tire?
I would guess Ball joints.
At 140K, I guess all of the stuff you listed might need replacing! I’d check everything you listed. Since you work on this stuff yourself, I’d pull the front struts and take the modules apart to check the jounce bumpers, mounts and hand-stroke the struts. You can check ball joints and tie rod ends at the same time for slop as well as stab bar links. If there’s anything wrong, you’ll find it.
Check for a broken strut spring.
equinox has a few issues with TSB’s. caliper guide pin bushing might fix a rattle over bumps. the rear bushing on front lower control arm has been revised also. an aftermarket control arm for same money might not have new design bushing