Excise liability for modifications to fully built motor vehicles...

Excise liability for modifications to fully built motor vehicles depends on whether refining or remaking amounts to manufacture and, where a Chapter Note is invoked, whether a body was built on the chassis as received. These foundational questions require fresh determination before excisability and chassis-based exemption can be resolved. Extended limitation requires a positive, deliberate suppression or misstatement intended to evade duty; registration, returns, departmental scrutiny and a bona fide exemption belief do not establish that standard merely because the departmental view later changes. Any duty determined is confined to the normal limitation period. Penalties for the manufacturer and its Executive Director require the same fraud or intentional-evasion conditions and therefore do not arise absent such conduct.