The SRT moniker stand for Street and Racing Technology. With respect to the Challenger, SRT and SRT8 are synonymous. SRT also did the SRT4 Neon and Caliber and there's been speculation about an SRT4 Dart. With respect to the difference between the SRT and SRT Core, large is correct - the Core version is sold without all the creature comforts of the standard model and at a lower price.