516. "Resident" means any person who manifests an intent to live or be located in this state on more than a temporary or transient basis. Presence in the state for six months or more in any 12-month period gives rise to a rebuttable presumption of residency.
The following are evidence of residency for purposes of vehicle registration:
(a) Address where registered to vote.
(b) Location of employment or place of business.
(c) Payment of resident tuition at a public institution of higher education.
(d) Attendance of dependents at a primary or secondary school.
(e) Filing a homeowner's property tax exemption.
(f) Renting or leasing a home for use as a residence.
(g) Declaration of residency to obtain a license or any other privilege or benefit not ordinarily extended to a nonresident.
(h) Possession of a California driver's license.
(i) Other acts, occurrences, or events that indicate presence in the state is more than temporary or transient.
Just do as few of these as possible. California DMV is the worst.
As for registration, smog it somewhere on the east coast to see if it will pass CA standards, if not, you should get it fixed before coming out here and trying (way more expensive).