A panhard rod should help if all the SSL bits are tight & set up right.It made a big difference to my Rover engined +4. The +4 with the T16 stock was stated as 136bhp . It stopped the back stepping out but you quote hopping which to me implies spring wind up and axle tramp.

For a Panhard rod explanation see here

Talking to SSL seems sensbile to me.

Last edited by John V6; 17/01/23 08:53 AM. Reason: Added T16 data
JohnV6
2022 CX Plus Four
2025 MG ZS EV aka Trigger