More details on the much-rumoured 'baby' Porsche have emerged, courtesy of our sources in Germany. The new model, which will be based on a mid-engined platform debuted by the VW Bluesport concept, is set to carry the legendary 550 tag of the original 50s Spyder.

It is also set to feature an all-new engine – a 1.6-litre flat-four-cylinder 'boxer' unit. This will be turbocharged giving a power output of around 200bhp. Driving the rear wheels through a conventional manual gearbox – although a PDK twin-clutch could be offered too – the new sub-Boxster machine will arrive in 2014.

There are no details regarding performance, but weighing around 1,200kg, the two-seater should be able to do 0-60mph in around 6.0 seconds and hit a top speed of 145mph. But it will also be efficient, returning 40mpg and emitting less than 160g/km of CO2 thanks to start-stop.

With a manually operated folding canvas roof, the two seater 550 will be a very back-to-basics Porsche. Smaller than the Boxster, it will be even more agile and one of the most driver-focused cars in the line-up.

The same mid-engined platform will spawn a production version of the VW Bluesport – which was revealed at the 2009 Detroit Motor Show – and an Audi-badged roadster o sit below the TT, badged R4. The latter will move the TT upmarket in terms of price, and the same will happen with the 550 and Boxster, with the new entry-level model starting at around £35,000 pushing the Boxster to £40,000+.