I know that....

As far as I remember the way Neuspeed made their lowering springs, they look like OEM springs (same amount of coil, just closer together) so that the fronts wouldn't be confused for the rears.

Well this is the front supsension


This is the rear suspension


Don't know if that helped...

I guess the way you could differentiate is that the coils for the rear slightly taper at the bottom where as the front springs remain the same diameter throughout the entire body of the spring.