The midsize Peugeot 308 is one of the most flexible vehicles in the French carmaker’s lineup, spawning numerous variants such as the regular three and five-door hatchbacks, SW wagon, as well as the stylish CC convertible. However, there is at least one more 308 variant in the works and it’s destined to be the most exciting of them all.

The car, spotted here with very little camouflage, is the production version of 2007’s 308 RC Z concept, a sporty coupe with similar proportions to the original Audi TT and a punchy turbocharged four-banger. Peugeot confirmed the 308 RC Z was headed for production and that the car would be revealed at this year’s Frankfurt Motor Show.

Called an 'Audi TT copy' by many, the new 308 RC Z captured here was undergoing testing in Spain this week. The nearly undisguised photos show the car will bear a fair resemblance in proportion to the Audi TT, though no observer is likely to confuse the two. Heavily flared fenders, a longer rear deck line and Peugeot's chunky front-end design - still slightly obscured here - will make the 308 RC Z stand out from the crowd.

Mechanically, not much is yet known, though the concept car sourced a 218hp (162kW) 1.6L turbo four from the Peugeot 207, and talk of an up-rated 250hp (186kW) variant is also circulating. With figures like that, the car will definitely have to focus on nimble handling to meet its performance targets. The standard range of engines available in the 308 is also likely to be available.

The February sighting of a mysterious 308 test mule using the standard hatchback bodystyle (see gallery below) suggested that engineers were working on adding another variant to the car’s ever-growing lineup. The wider rear bumper and extended wheel arches seen in those spy images indicated that the new model would be a much sportier version than the regular hatchback. It's not certain what that car was - in addition to being a mule for the RC Z, there was a possibility that Peugeot could also be preparing a sporty 308 GT or RC hatch - similar to the 207 RC - or it could even simply be a facelifted standard model.

With the emergence of this new set of spy photos, however, it's clear that Peugeot is well along the way toward the development of the 308 RC Z Coupe, and we can expect more details to appear as we approach September’s Frankfurt Motor Show.