Silver Lodge Plugs

[Aibrucia@domain.elided]

I understand the HL and 2HL aka Golden Lodge plugs are recommended by Alfa 
for the 4 cylinder cars. 
Alfa recommends the HL-E and 2HL-E for the 6 cylinder cars.  What is the 
difference between the Gold and Silver series? I note that International 
lists the Golden Lodge plugs for BOTH the 4 and 6 cylinder cars.  
Thanks

Tony Brucia

------------------------------