I seen civic springs of up front being used on Starlet rear struts as they coil the same but are much stiffer The front I would suggest universal coilovers springs to height and stiffness
Fit the Starlet ct9b turbine shaft into a ct12b now fit the cartridge back to Starlet turbine housing now you have a little monster that will out perform a stock tdo4-13t I know as I have me 1 off these