Digging this thread back up since i am in the process of researching some stuff to do on my rear suspension
It appears SPL has updated their mid-link so it comes with an "adjustable" top hat now. Should allow the spring to be seated better
Rear Adjustable Toe Midlinks for the 370Z and G37 | SPL Parts
I've emailed them about whether this can be purchased separately
I'm trying to map out how an air cup system will work in the rear, from StanceParts. Might need some machining