Samuel Egbo and Melissa John both pleaded guilty to conspiracy to burgle for their parts in the conspiracy which saw 38 cars stolen from 12 dealerships during an 18-month period.
Egbo (25), was jailed for five years at Southampton Crown Court while John (24), was jailed for two years.
Anthony Hawes (21), was jailed for 15 months for an offence of attempted theft of a motor vehicle from a Toyota garage in Salisbury, Wiltshire, on May 8 last year.
A fourth member, Daniel Browne (22), pleaded guilty to conspiracy to burgle on September 3 but failed to attend yesterday's hearing and a warrant for his arrest was issued.
The court heard that a total of 38 cars, including makes such as Mercedes-Benz, BMW and Chrysler Jeep, with a total value of £613,958, were targeted by the gang, all from east London, between April 2002 and September 2003.
The vehicles were stolen from showrooms in London, Hampshire, Wiltshire and Warwickshire. Only 75% of them were recovered, in the London and Home Counties areas. Egbo, who grew up in Nigeria but moved to the UK where he was privately educated, admitted being involved in seven of the burglaries between July 2002 and July 2003, during which cars to the value of £387,860 were stolen, the court heard.
John admitted her part in two burglaries in July and December 2002, in which cars worth £52,500 were taken.
The court was also told that Browne was involved in seven burglaries during a 17-month period, in which cars worth £192,050 were taken.
Hawes was only involved in the one offence, the court heard.
Sentencing Egbo, Judge John Boggis said he understood that addiction to crack cocaine had led him to be involved in the conspiracy but he had become a major player in the gang.
The court heard that the conspiracy was discovered in a joint operation by Wiltshire Police and the Metropolitan force. A spokesman for the Crown Prosecution Service said the gang had been investigated for burglaries in which cars with a total value of £1.2 million had been taken but it had been decided to accept the guilty pleas to the thefts of cars worth about £600,000 for which the defendants were sentenced.