Look at the glittery blue paint in this close up...it's like what's on a real car!

Matchbox gets in on the action by plastering Sonic X images onto some of their famous metal tiny cars. Each car is a real type that you can drive, such as Sonic is on a Pontiac Piranha, Tails is on a Volkswagen Beetle 4X4, and Knuckles is on a Chevrolet Suburban. They themed the cars with the character, name, and tiny Sonic X logo as an added detail. Each one really rolls and is made of metal. They were available individually (seen here) or as a multi-pak. The individuals are confirmed at Eckerd (a drugstore) in the USA. The multi-packs were available at Target, and Toys R Us in the USA. They started around 2004, but many hung around until at least 2006. 

The multi pack contained all 5 cars, but doesn't tell you what type of car they are. As you see above, Eggman is on some sort of panel-van and Chris is on something like an SUV. Neither of these have glittery paint like the Sonic car. Eggman's is blackish/brown. The Tails car has a clear/yellow plastic light bar on the top (it doesn't do anything) The back of the multi-pack is also open to view and doesn't really have any info or extra art. The pack is in the collection of SonicGear.