Thoughts on KYB spring/shock upgrade sa mirage?

2014 Mirage HB 59k KM ODO

Issue ko ngayon may rear sagging tapos medyo bumpy yung ride quality. I know ganito talaga nature ng suspension nito and Mirage HBs in general, pero parang lumala na ngayon.

Currently looking at K-Flex coil springs to fix the sagging and KYB Excel-G shock absorbers for the rear.

Ano ba magandang setup nito?

Option 1: rear springs + rear shock absorbers lang i-upgrade
Option 2: front and rear springs tapos rear shocks lang
O may mas magandang combo ba kayo marecommend?

Goal ko sana is ma-fix yung rear sagging and hopefully improve the ride quality sa bumpy roads.

Also tanong ko rin: saan ba mas malaki effect ng shock absorbers sa ride quality, sa front ba or sa rear?

May naka-try na ba ng ganitong setup sa Mirage? Kamusta ride quality and ride height after?

Thanks!