My P11-144 I bought two years ago is still going strong. Only major work required was a rusted exhaust. Brakes are still good, engine sound. Got a slight knocking on front left, but I think that's body work as I manhandled the wheels with no play.
It doesn't knock when turning right, or even over uneven surfaces, under breaking, or speed.
Only thing Im slightly concerned about is the slight judder from the clutch when taking up second. But then Im still not used to a manual. Still keep stalling it. It's the accelerator, I either get too many or not enough revs.