It's alleged the syndicate has been targeting cars parked in public car parks, on the street and at private businesses across Melbourne.
Among the 21 vehicles seized was a bobcat, tow truck, minibus, custom Holden Caprice, Toyota Hilux, Ford Ranger, and several trailers and motorbikes.
Police also seized multiple sets of keys and electronic key reprogramming devices. Key reprogramming was allegedly the method used by the offenders to steal the vehicles.
Officers also seized multiple false and stolen registration plates, a window breaker and other tools, and $3,800 in cash.
The first search warrant was executed on February 3 at a property in Wildwood, where 10 vehicles were uncovered.
Police recovered the remaining 11 vehicles and arrested the two alleged ringleaders during further search warrants across Melbourne's west on February 16 and in Melbourne's north the following day.
Hume CIU Detective Acting Senior Sergeant Joe Hartwig said police would be relentless in bringing those responsible to account.
"Car theft remains one of our biggest priorities," he said on Monday.
"With the prevalence of technology making it easier to steal cars, we encourage all car owners to take precautions to help lower the chances of having your car stolen."
Two Sunbury men, aged 34 and 35, face more than 60 charges, including multiple counts of burglary, motor vehicle theft, handling stolen goods, recklessly exposing police to risk by driving, and committing indictable offences while on bail
They have both been remanded to appear at Sunshine Magistrates' Court on March 3.
Two other men from Wildwood were charged with handling stolen goods and were bailed to appear at court at a later date.
Victoria was the worst state or territory for car crime last financial year, when about 12,000 vehicles were stolen, marking a 59 per cent increase on the previous year.