[maupineda]

I found your posts very interesting as that is exactly what I have been thinking about doing. My car rides on H&R Coilovers, and it is overly stiff and I have been looking at TCK springs, just trying to figure out what rate would be best for my needs. they have linear springs only, rating from 400 to 700 in increments of 100's.

Your 10k springs are ~550, which is a nice in-between from what I have read. the most feedback I found was about Z3M users (Z3Ms are lighter, but have similar suspension design and 50/50 weight distribution), and in general, they said a 400 and even 500 spring would be soft, and that 600 is the sweet spot, with those cars being lighter I would think for our platform we may need a slightly higher rate, but maybe this logic is plain wrong. A guy who claimed to be a suspension designer said that for the Z3M a nice rate for street and track with appropriate dampers is 350/500

Anyhow, you seem to have a rate I would consider a happy mean, if you just want to raise and soften it, you could go with TCK 500 and take the hit and mess with the adjusters to set it where you want even though they are a PITA.

I wish I knew the rates H&R use, I just know they are rock hard, and progressive coils are consumed with just the weight of the car leaving just the stiff coils as active, which makes the ride very crappy. I read somewhere the stiffer section of the spring can go from 700-1000 lb/in, and that is too much. in my case, I am almost ready to buy linear 600 for my setup and try it out.

lastly, I have found that from the factory the rear hight is set 13mm lower than the front (referencing the wheel and fender arch), I assume this is needed to achieve the 50/50 weight; if the rake is inverse, then you are shifting some more weight to the front, I don't think it is a big issue for normal driving, but this will affect how much weight the rear carries (less) which adds a bit to the crapy ride if that makes sense.