If your car is a Quantum Mk1 Saloon (with a hatchback) then it uses Mk3 Escort track control arms and anti roll bar. If it's a Quantum Mk2 Coupe (with a boot) then it uses Mk4 Escort track control arms and anti roll bar.
On the Mk4 Escort the track control arms are all the same, the Escort RST ones are the same as the non RST one. The Mk4 anti roll bar/tie bar was used in 2 different diameters, 22 and 24mm, the XR3i and the RST using the larger diameter one, this only effects the front anti roll bar mounting bushes though, the track control arm is the same for both sizes of ARB.
Now, if your Quantum is a Mk1 saloon then it's possible it was built using parts from a Mk3 Escort RST, the front suspension on these was very different to the other Mk3 escorts as it had separate tie bars for each side and then an anti roll bar as well which was clamped to the tie bars rather than being a combined unit as it was on the other Mk3 Escorts and the Mk4 Escort. But I'm not sure if this setup could be fitted on the Quantum.
