The decision was obviously not well-received by the community. Thankfully 72 of them can still be stolen off the street, but 123 are currently completely unobtainable. Rockstar mentioned that the removed vehicles 'would be made available via events showrooms, The Lucky Wheel, and other places'. As part of the recently released San Andreas Mercenaries DLC, Rockstar Games removed 195 vehicles from being able to be purchased in GTA Online via the in-game websites.
