Go with the GSC S2's
Just like anything else, its all in the setup. Tough to really compare the two without doing it on the same car/setup.From what I've personally witnessed, I've seen the better results locally from Kelford -B's vs. GSC S2's. 700whp you'll want something larger than either of these though.
You gotta let people know right!As lopey as your tuner sets them. I initially had them completely smooth and then added the lope to them later on.