Most Miata's are totaled from front collisions (the damage is pretty extensive). A rear-hit car really only damages a few body parts unless it gets into the differential mounts and breaks the carrier, leaving the whole front 1/2 of the car in good condition. A front-hit Miata is also cheaper at the auto auctions. Rear-hit cars still have most of the easier parts to sell (at high prices) in sellable condition, so they go higher and faster at the auctions.