Hello David,
i don't think it's an overtightened cross member. But you could check if you loose it a little bit.
Did you check the part numbers on the new springs? Are they the same?
Can you compress the chassis if you press down the fender – not too much force, please – don't put a big dent in your fender
? Or is it a kind of blocked. That would mean there is something wrong with the parts order or with the damper or spring.
Also keep in mind that it takes a little driving time before the chassis settles to it's final ride height. But both sides (left and right) for shure have to have the same height after installation.
Regards, Markus