After buying a set of 4 lowering springs from a seller on flea-bay, i discovered that PI’s springs sat at standard ride height at the rear!
after much measuring & conversation with the seller, we agreed i had the right springs, but on my '90 Eunos they definitely weren’t 30mm lower.
I ended up cutting one entire coil off of the rears to get it to sit right ( i.e not like a demented off-roader!).
The ride is fine, and the springs seemed ok, but there is definitely a ride height issue with these.
I have to say i can’t blame the seller, as they were dispatched direct from PI, but they certanly dragged their heels in sorting a resolution.(we did consider fitting their 45mm lowered springs, but i gave up and got out the angle grinder)
Be warned!
Regards
Andy
Sounds like you had the wrong ones delivered
, this is what a -30mm PI lowering rear spring looks like next to the spring that came off (admittedly Mk2 Bilstien suspension fitted to a Mk1)

Well, i think we can safely say that the bilsteins are completely different!
According to the Mazda Workshop manual, the standard rear springs are 339.5mm . 10mm dia. and 7.68 coils.
The PI ones i was sent (and as i said, the seller confirmed with PI they were as they should be) were 332mm long., but 9.25 coils. which should result in a greater drop as more coils = more sag for the same length, however, they didn’t!
Andy
Are you sure the old ones were original? Did they measure up ok or had they maybe sagged a bit?
Yes, the old ones were 7mm longer overall, so i know i had all the facts correct.
So in summary!! watch out PI 30mm lowering springs don’t lower the car at the rear!