http://progressauto.com/store/produc...roducts_id=303

These are 1" drop front and rear with 425/385 spring rates with a lifetime warranty!

Might these be the best off the shelf performance springs available for the 350Z now? Combined with the Tokico D-Spec shocks... mmmmmm.

 

http://www.andysautosport.com has the Progress springs for $171 and the Progress swaybars for $270. Badass combination!

 

Wow, that's the first I've seen for stand alone springs where the front has a heavier rate than the rears.

 

Hotchkis and Tein H-Techs as well as others have higher front springrates

 

The progress springs are also progressive, and initial springrates aren't listed so its hard to tell how good they will actually be

 

Doh, didn't catch the progressive part.

 

I got Progress Sways and I love Progress. I say go for it.

 

After speaking with a representative from Progress and receiving the run around about their spring rates I have decided to take matters into my own hands. They informed me that their springs were progressive, yet had a static rate of 425 F and 385 R through out the entire range, give or take 15 lbs. Wouldn't this make the spring linear? They say no. I asked for the initial rate and they said they didn't do the R&D to give out that information. Hmmmm.... sounds like a great suspension company eh?

In the next week or so I will have the springs' actual numbers. I am going to either purchase or borrow a set from a local shop and take them to a different suspension specialist who has a spring rate tool that will reveal their actual rates through the compression range.

Updates to come...

 

I've called Progress a few times over the years for various specs and it's alway's been one of the better experiences for me in the industry. I really don't understand why they acted like they did and said what they said. It would be pointless of them to go to the effort of making the springs progressive if they didn't change rate at some point in the suspension's travel range. If not, they would have made linear springs. Since these springs have at least 3 coils that are dedicated to being part of their progressive nature, it's within reason to say they will have a somewhat wide rate spread between initial and final rates. IMO, take about 100lbs out of the peak rates to have your initial rates.

 

They openly admit that they won't clear many aftermarket exhausts however OE and Nismo should be fine. They are solid bars and pretty cheap, $130 a piece from most places, such a P-Tuning(local to us). That's probably my next mod along with a new lsd.

 

Well, did you get the progress springs installed? Any pics?