This kind of ties in with my question about what the hub to guard height is as standard.
I put kings kffl 13 in my v6, which are meant to be a 1in drop. Hub to guard is 330mm but the top 4 coils are closed meaning the soft end of the progression is doing nothing and the ride is harsh. Wilkinsons say that is normal, kings web site says the opposite. Kings ignored my email asking for more tech info.
So I fitted Burtons cs118. They are also meant to be 1 in lower but they sit at 370mm hub to guard, 40mm higher than the kings, so one of them has got the ride height wrong. The rate is 145 which is nice, but they are too high. I think the kings are a touch too low for decent guard clearance. I will probably try another set of Burtons and dump the kings onto ebay. From what the guys at Burtons have said the next size down will be spot on for height and ride at 145 lb/in is nice. Tech support from Burtons has been 1st class and they are cheaper even with freight.
I tested 2 other sets of springs but they have measured rates of 110 lb/in so I dont know what they are from.
So my 2c forget kings, they wont want to help, talk to the guys at Burtons. I have a lot of data and now have a spread sheet that calculates ride height quite well, but need to take a few more measurements yet.
Is yours 4cyl or 6?
What is your starting hub to guard height?
Also when you drop the car back down, push it back about 1m then push it back forward. This is because it lowers on an angle so you need to rotate the wheel to get it to sit right. Then take your measurements.