Most things I've heard about the BBK Long-Tubes are negative. From what I've read, the primaries don't port match with the exhaust ports coming off of the heads. The BBKs have oval ports while the heads on Mach 1s have rectangular exhaust ports, so they aren't doing much good. I'm sure they've probably fixed the problem by now, but BBK is still a 'cheaper' brand overall. The best headers you could possibly buy with the best power gain are some Kooks Long-Tubes. The price is around $900, but you get what you pay for... might as well save up and do it right the first time.