Bugscraper wrote on 12/31/69 at 16:00:02:I'm in CA; I think changing exhaust has been illegal for awhile. We have a local HA chapter here; I wonder if that'll influence enforcement.
I'm pretty sure that the regulation that banned modifying anything that might effect emissions has been in effect sind the 1977 Clean Air Act Amendments became effective in 1979.
The 2006 changes are just lower emissions standards. There's a lower standard coming in 2010.
The one bike per lifetime exclusion allows a person to build one bike from a kit, IIRC.