"They" refers to the seller of the parts which I bought on eBay. Seller said he would send me the correct springs, but since he messed things up twice, I would like to try to verify that they are the correct springs when I receive them, which should be next Friday.

The struts are definitely correct because the part numbers are for a '15+ Nismo as are the shocks. I suppose it's not 100% certain that the front are correct. Since the part number of the spring does not appear on the Spring, I don't know of a way to confirm that the springs I will receive are from a Nismo. If someone has '15+ Nismo springs, could you measure the length and see if there are any identifying marks? I know Nissan uses paint spots but I'm not sure what the colors mean.

I swapped the wrong spring for the stock left rear spring and then removed the right rear shock and replaced it with the nismo unit and went forca test drive. So to recap, the car now has the 2015+ Nismo front struts and nismo rear shocks but stock rear springs.

The car is definitely more jiggly...firm and you can feel more bumps. However, it's not terrible at all. It feels more like a sports car. The car corners flatter and is more responsive. I think the OEM Nismo suspension is a great option for someone who wants a firmer ride but does not want to lower the car.

I received alleged Nismo rear springs from the seller. They are identical in every way to my stock springs....spring wire thickness 15.03ish mm, length 12 inches, paint marks 2 green and 1 pink, number of coils 5, and coil shape. Can someone with a 2015 nismo measure their springs and let me know. The springs wire thickness can be measure without removing wheel but the rest needs wheel and spring removal.

My spring on bottom, and spring I received on top.