[tony209]

These are the KYB springs I have:-
RC5923 rear 400mm (stock 430mm)
RA3789 front 442mm (stock 460mm)

These springs are recommended for both the coupe and the cabriolet. I removed the KYB rears because the ride was too firm, although the lower rear ride height improved rear visibility!

I fitted Suplex 38100 springs at the rear as these are the the original stock length (430mm).

With the KYB springs on the front and the Suplex on the rear, the ride height at the front is at least 18mm lower than factory and possibly more than that due to more weight being transferred to the front.

Below is a comparison of the Suplex rear spring (left) and the KYB rear spring - if I still have the original Volvo rear spring, I'll take a comparison picture but I can assure you that the Suplex and the Volvo are the same length.

When I swap the KYB fronts, I will take a comparison picture with the Volvo original dynamic (brown) spring.

I don't know what the spring lengths are for the factory lowered dynamic springs but I would suspect that KYB used those figures.

Regarding the Koni special active shocks, they do say that they are not suitable for lowered ride height, not sure if this includes factory lowered or just refers to aftermarket lowering.

If you decide to buy the Koni shocks, I would suggest you buy the fronts first, I didn't find any difference in fitting the rears and even Koni suggest that you can fit the fronts only.

I still thing the biggest problem with the C70 regarding the firm ride is due to the high weight at the front. The car was designed by TWR (Ian Callum) but I think they were limited to what they could change with the P80 chassis.

The P2 V70 (Y2 chassis) is much lighter, front tyre pressures are 31psi compared to 35psi on the C70. The P2 chassis is so well sorted that when I changed from 15" wheels with 195/65 tyres to 17" wheels and 225/45 tyres, there was no difference in ride quality.