The M3 is expected to arrive first, at the start of the year, with the M4 following much later in 2014.
Power for both cars will come from a 3.0-litre turbocharged straight-six engine, producing around 450bhp – that’s up from 414bhp.
This hike in power will be combined with a weight reduction of around 40kg over the previous M3 to slash the 0-62mph sprint time by about six-tenths to around four seconds flat.
As ever with M cars, the styling upgrades on both models are set to be subtle, including a more aggressive bodykit, M-specific alloy wheels and a power bulge in the bonnet.
The M3 is expected to cost around £60,000 at launch next year, with the M4 slightly pricier.