Hi Heinz
It was a ride in Craig Jezz's 4/4 that convinced me to get BRB's and a Panhard Rod. The BRB's improved the shuddering front end on bumpy roads. I might have been happy with just the BRB's however I was glad I later fitted the Panhard Rod though my initial reaction was that the rear ride was firmer (though I don't see why it should be). Not uncomfortable though and the car is more stable and probably easier to driver. Mine is a SiFab Panhard Rod by the way which as you are probably aware are similar to the Mulfab PR.
Rob, which model year is your 4/4? Around 2011 they changed from Salisbury to BTR rear axles. Good to know it works so good with your 4/4. So I will go this path. In my view the rear ride is firmer with a PR because it is the PR which controls the rear axle against lateral movement. So without the PR the chassis moves sidewards before you feel the connection to the road and therefore the forces which build up when cornering, if this makes sense. It is always a short period of time where one feels uncomfortable before the car „bites“ when you slide above the rear axle with the chassis.
Just a thought regarding Robbies‘ experiences with under and over steel behavior. When the chassis has lateral play at the rear without using the PR could it be possible that the relation of the angle and/or the track between rear axle and front axle varies and so the willingness to turn in is weaker when the rear axle is wandering to the inside of the body, e.g. to the right in a right curve or in other words the rear of the car tends to go left in this curve, and with it the corresponding angle of the front axle.
