In Japan, it's called the RX-7 Sport Prestige Limited. They claim nothing extraordinary except for cosmetic differences and minor chassis tuning. The most important of these changes include stiffer dampers, more rigid roof/pillar structure, urethane bushes for front crossmember, and slightly bigger brakes. Exterior changes include semi-gloss finishes for the headlight and taillight assemblies. Also included are the fog lights, new rear spoiler, and deep gloss wheels. Interior changes include difference coloured trim, new steering wheel with stereo controls, beige leather seats, and VW-style flip keys.
Some guy in the marketing group at Mazda North America probably asked what "evolution" was in Japanese. (obviously thinking about the Lancer) Another guy with a dictionary shouted out "SHINKA!" Then all was said and done with that matter.