Just an "FYI" on how H&R does their springs.
In general, H&R doesn't adjust really adjust spring rate for weight like BMW does (a 6cyl front car will have a stiffer front spring than a 4cyl one), but instead they tend to use the same spring rate for all models, and then only vary the free length of the spring depending on the vehicle's weight (or xdrive vs rwd).
Below are spring dimensions and assignments from H&R's G20 TUV documentation:
You'll notice that springs "1" and "2" for both the front and rear axles have the same wire diameters, same number of coils, and same external diameters. This means that these springs will have the same spring rate. The only difference between them is the free length. Since they have the same spring rates, springs "1" and "2" will compress the same amount given the load, so the height difference between them will just be the difference in starting length. So spring "2" will be 9mm higher than spring "1."
The F30 330e had higher spring rates than other F30 models due to its higher weight. For both the base suspension and M-Sport trims it had the same springs as the 4-cyl F34 (3-GT) xDrive, which was the heaviest F3x aside from the convertible.
H&R could end up recommending the "2" front spring and "4" rear spring for the 330e since the "2" front spring is sufficient for the 6cyl 330d front, and for the F3x generation they used the same spring for the wagon and GT in the rear.