Rumors about a GS F have been swirling for years and now our spies have managed to catch a prototype in a garage.

Caught wearing a GS body, the development mule sports a four-tailpipe exhaust system that is a trademark of all F variants. There isn't much else to see but the production model will undoubtedly feature a sporty body kit with modified bumpers, revised side skirts and a prominent rear diffuser.

The model is also slated to feature a sport-tuned suspension, high-performance brakes and unique interior trim.

Little is known about what will power the model but IS chief engineer Junichi Furuyama recently hinted the 5.0-liter V8 engine - from the IS F - could be dropped to meet Euro 6 emission standards. He went on to say the RC F, and presumably the GS F, could use either a naturally-aspirated or turbocharged engine but he favors natural aspiration because it offers a "more pure experience." Regardless, speculation suggests the model will come with a V8 that develops up to 460 bhp (343 kW).

Gallery: Lexus GS F prototype spied in a garage

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