i like the duals (mine sound awsome), lower profile and i heard you have to cut the tow hook to get the single N1 to fit (im not sure, feel free to correct me), i know the dual N1 has the same initial Piping diamiter (80mm or 3 inch) as the single and has the same flow rate, but there really is no advantage to the duals over the single N1
EDIT: oh yeah, i got mine from enjuku racing for 550 shipped, it took 3 months and they came with two big dents in one of the canisters (right where you can see them!

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