I have Apexi N1 EXV coilovers on my 9MR, originally installed with 8k springs front and rear. It's too pushy, and I don't like bar.

The coilovers are valved for the retarded 8k (F) /6k (R) rates. Assuming +/- 2k is fine without revalving, I am putting on some hard skinny tires for the winter, and figure I'll try 6K/8K for now. Come spring, I'll get some soft fat rubber and experiment to see how the rears cope with 7k/9k or even 8k/10k - or just get a better set of coilovers if I can swing it. The Apexi's have turned out decent after some early newb problems, but I can see their limits.

Current springs are 62mm ID 180mm length 8Kg/mm front and rear. Two questions follow from that as I look to swap them:

1) I've found that the 62mm ID isn't very common. Swifts are in 60mm or 65mm, Eibachs are 2.25" or 2.5". What works on the Apexi perch? Anyone have experience using other ID springs with these coilovers? I expect the perch to be identical to that used on Megans, so experience with Megans should be applicable.

2) With the rate swap should I mess with free length - ie, will I need a longer spring, since it will be compressed more under load?

Also... My fronts bind quite a bit... My wife will keep reading email while I go screaming through an entrance ramp with naught but a slight scowl - but the twang in the parking lot makes her jump! Any recommendations for thrust bearings or other solutions?

 

I would measure the inner diameter of the spring perch and go from there.

The longer the spring the higher you can raise the Evo. The shorter the spring the lower the Evo will sit.

Long springs = Higher Adjustable Ride Height
Short springs = Lower Adjustable Ride Height

With the rate swap it wont matter. The spring will compress and rebound according to its spring constant(+ dampening ratio of the shock) not the length of it's body.

One could try some white lithium grease spray on the billet tophats and if that doesn't work one could replace with the OEM tophats. In my experience the OEM tophats are always quieter.

 

For anyone else who runs into this...

I installed 2.5" Eibach springs on my N1 ExV's. 2.5" thrust bearings are also sitting well.

The only problem is that one of my struts is bent - discovered when I went to adjust the ride height. Weee. Apexi won't sell a single strut, either - I can send it in for a rebuild, but then I don't have a car for however long it takes them. Joy.

After dampening adjustment, 350 lbs/in (6.3k kg/mm) front springs and 8kg/mm are working reasonably well, even with the standard apexi valving. It is a bit soft for my taste, but the improvement in balance is worth it, and I think this is just about right for a daily driver on OE size 340 treadwear summer tires.