Frog, I was told by AJUSA that the 4 cylinder Koni Sport kit uses different springs in the front due to the difference in weight between the two engines. They specifically said that the struts are identical between the two kits.
Read more about my current agonizing over this little detail here if you'd like:
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=susp&Number=1209913&page=0&view=collapsed&sb=5&o=7&fpart=1