I'm getting vibration and a thumping noise from under my 420SEL on braking, there is some pulsation from the brakes that feels like the rear rotors are warped, but the thumping makes me think I have bad motor mounts and/or worn suspension bushings. This is a 170K beater but I still want it to drive reasonably well. There is a different noise over bumps that I believe is suspension-related, but the thumping on braking feels like heavy stuff is moving around under there. Any thoughts for diagnosing this?

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2002 Ford ZX2
2 x 2013 Honda Civics