The facelifted Porsche Boxster will receive uprated styling and a new four-cylinder engine when it goes on sale in the UK at the start of next year.

The revamped third-generation Boxster is due to receive its global debut at the Frankfurt motor show in September. Styling changes for the reworked roadster include a revised front bumper with new air intakes, and altered light clusters. The car’s interior is also expected to be upgraded, judging by the camouflaged cabin of this latest prototype.

However, the biggest change looks set to take place in the engine bay, where Porsche is set to introduce a new horizontally opposed four-cylinder powerplant as part of plans to broaden the appeal of both the Boxster and its fixed-roof sister model, the Cayman.

Already confirmed by Porsche chairman Matthias Müller, the new engine is planned to be offered alongside upgraded versions of the existing Boxster’s horizontally opposed six-cylinder engine.

“We will continue with the downsizing strategy and develop a new four-cylinder boxer engine, which will see service in the next-generation Boxster and Cayman,” Müller confirmed last year. “We will not separate ourselves from efforts to reduce CO2”.

When queried on the output of the new four-cylinder boxer engine, Müller said it would produce “up to 400ps [395bhp]”.

It’s expected the new flat four-cylinder engines will support 2.0 and 2.5-litre capacities, with power outputs from 210bhp through to the 395bhp alluded to by Mueller.

The six-cylinder boxer engine used by the existing Boxster and Cayman develops 261bhp and 271bhp respectively in 2.7-litre form, with a larger 3.4-litre unit offering either 311bhp, 325bhp or 335bhp depending on the model in which it is deployed.