Miata / Accord coil springs, depend on what you want.
For a little Stiffer Ride, getting rid from saggy butt with loads,
I chose Honda Accord front coil springs on the Rear,
Huge imptovement... I suggest you read the article whose link is on my post above.
Edit: Here it is ~► https://www.ultimatesubaru.org/forum/topic/106807-improved-shock-absorbers-and-spring-coils-on-loyales/
Has further details and photos...
Kind Regards.