Kyb just released this here in the philippines, they made this specifically for the mirage.
Coil specs are the following, got this form our local forum.
1. Spring rate: 2.3kg/mm (at stock height) compared to the stock which is 1.9kg/mm
2. Diameter: 10.3 mm compared to the stock which is 9.3mm
3. Height: 310 mm or 12.2" so still stock height.
Comparing springs (left is oem, right is kyb)
Note the difference in height.
KYB thought of this to maintain stock height.
My impression for the past 2 days. Rear got stiffer as expected, sharper steering because of less body roll during abrupt turns. Overall at least 30% improvement compared to the oem rear springs.