I don't get you coug... 13 x 166,000,000 = 2,158,000,000 = 2158mHz = 2.158ghz which is closer to the 2700+ than the 2600+, but still inbetween thw two.
Are you saying that the FSB is not 166,000,000 (+/- a few percent)? is it really 166,666,666? I think that really just depends on the clock...