The third car build under the MLP theme (This is actually the last one I kept track of in sense of order) is Rarity.
The car used is the Karin Sultan RS (an in-universe Lexus IS, Mitsubishi Lancer Evo VI, Subaru Impreza), with an ice white and purple paint job, blue linings and wheels (which was supposed to mimic her three gem cutie mark), a deep purple neon, a deep blue interior and an elegant powerplant.