When the new adjustable perch Koni shocks were announced for the ND, and I saw them on your website, I couldn't wrap my head around how lowering the bottom perch by "X" amount could lower that end of the car by anything other than "X" amount (like how can the next lower perch lower base springs by 30mm and Club springs by 20mm).
Then it dawned on me that the stock springs are set up with some amount of pre-load on the fixed perches, and by lowering the bottom perch, you reduce the pre-load. Then it makes sense that the drop will always be greater than the amount you lowered the perch until all pre-load is gone, and that if the base springs run more pre-load than the Club springs, changing the perch has a bigger effect.
That leads to my real question. Has anyone tried them with Roadstersport springs? Without knowing how much preload those have on the fixed perches, it's hard to know how accurately you can drop the front end to try to level out an RF when running the soft top springs. If anyone has done it yet, I'd love to see a picture of how it came out, so I can convince myself to go the Koni/RS spring route rather than the Koni/FM spring route on my RF.