How fast have you gone with exhaust manifolds?

Not all the FAST guys are running ExtrudeHoned manifolds so I wouldn't feel that it is a must. Does it help? I am sure it does, but realize they are looking to squeeze every possible thousandth of a second out of their cars and are restricted to using the factory parts without the option of running headers. IMO the extrudehone process on anything less than a very serious effort class specific car such as the FAST cars or the guys running in SuperCarRaces (http://www.supercarraces.com) will be costly and provide marginal if even measurable results. There are a few small block cars in the 12.0 high 11 range that are running stock exhaust manifolds that have only been cleaned up with a die grinder.