Rear Springs and Shocks . Update.

[Antm72]

You can get different size spring pads they do 5mm 10 15 and 22 mm you could just fit a larger one to make it sit flat.
Its not the fix but its a cheap work around until you get the fix done

 

[Dino D]

You can also remove one or both spring pads to lower accordingly without any il effect on ride I can tell.
It's approximately a ratio of 1.6 I believe i.e. You remove a 10mm pad and it drops around 16mm (something about the position of where the spring sits in relation to the hub).

 

[Brian H]

They was some discussion a few years ago about the uneven height at the rear of the car, when the car was designed it was designed as a LHD car and supposedly had a little extra height on the drivers side (for a LHD car) to compensate for the driver weight!

 

[Antm72]

They was some discussion a few years ago about the uneven height at the rear of the car, when the car was designed it was designed as a LHD car and supposedly had a little extra height on the drivers side (for a LHD car) to compensate for the driver weight!

I'd read that also when looking for answers

 

[Dino D]

I read somewhere a BMW 'driver' for their purpose was only 75kg...!
Maybe the Z being made in America had a slightly more generous allowance?

 

[ZTec]

You can also remove one or both spring pads to lower accordingly without any il effect on ride I can tell.
It's approximately a ratio of 1.6 I believe i.e. You remove a 10mm pad and it drops around 16mm (something about the position of where the spring sits in relation to the hub).

I'll get the car out tomorrow night and check tyre pressures to make sure I'm not running low on any tyres, take some more measurements and give it a good blast to settle everything then measure again. It probably was low on the passenger side before I changed the springs and shocks and I didn't notice. As mentioned it was built into the design to work with the weight of the driver so I suppose if it's not broken, don't fix it. The rear bushes are 19 years old now so they're not at their best, so changing those is not an option as it a big job so I hear.
Anyway, many thanks for taking time to answer my questions @Dino D, @Brian, and @Antm72.