SPY PICS: GT3 power for Porsche 718 Boxster Spyder

When the Porsche 718 Boxster Spyder was first snapped by spy photographers late last year, it was presumed that there would be a heavily re-worked version of the turbocharged flat four under the rear engine cover.

That theory now seems to have been discarded in light of a report out of the UK that the new variant would be powered by a 4.0-litre horizontally-opposed six-cylinder shared with the 911 GT3.

Designed in tribute to the 718 Spyder from the late 1950s, the Boxster Spyder features faired buttresses behind the headrests and a tent-like canvas roof. Those buttresses make the rear end of the Boxster look chunky and heavy, which was on the cards even without them, if there is truly a big, bad flat six lurking under there.

If the Boxster Spyder is to capitalise on the output promised by the flat six, it will likely be on a strict diet, perhaps adopting aluminium panels and doing away with standard air conditioning and the electric mechanism for the folding roof.

Porsche was understood to be planning the Boxster Spyder's debut around this time, but even though the vehicle is now testing undisguised, the launch date looks likely to be later this year.