A little late to the party, but I run:
Front Springs: Swift 7.0kg (392lb-in) / 7" length / 65mm ID
Rear Springs: Swift 12.0kg (672lb-in) / 9" length / 65mm ID
On the front, I have a custom spacer at the knuckle and this combination with the 7" spring works well as I have maximized spring travel (and minimized the risk of coil bind) - the spring is barely preloaded so we have maximum droop travel available.
I am thinking about a slight increase in rate - when I do this, if I had the option to do a 6.5" spring I would, but I think I will likely end up sticking with the 7" option which will fit the same as it does now but sit a bit higher on the ride height front.
On the rear, I could lower the car another 1/2" to 3/4" easily on my current adjusters so I believe the 9" spring is an ideal length without helper.
Cheers,
Mark
Ride height at rest:
