[jakeru]

There are specs, perhaps in Porsche service literature or parts manual, on spring wire thickness and ride height. I seem to recall the US-spec M030 had the thickest wire. I believe most of the lowering that happened on the euro-spec springs happened at at the front of the car and not as much as at the rear.

(Edit: found the ride height specs from the service manual - attached.)

But for the sake of philosophical argument, let's just assume for a moment that the spring rate on us spec vs euro spec M030 wire were the same. In this case, the bump stops would be engaged sooner (with less spring deflection required to engage the bump stops), thereby raising the effective wheel rate for the M030 spring sooner compared to the us-spec M030.