Not sure how long springs and shocks are good for (in terms of mileage)?

I've got a 2006 G35 sport sedan, and thanks to the stickies in this forum, have been hunting for unrevised 350z springs on here and my350z.com for the past month or so.

I've a chance to buy a complete suspension from a 2004 350z, and while I'm not sure I need the shocks as well (have 18k on my stock sports), the setup has about 44k miles on them.

Any G35's rolling on unrevised springs with higher mileage or any knowledgeable suspension peeps with some insight?

 

I was just about to post a question on the springs.
I sold a set of unrevised low mileage springs from a Z to a G owner and wondered about the differences.

I just picked up a used G and have an unused 03 Z with 973 miles I can transplant.

BTW the color of the dots on the springs will tell if it is the revised.