Both cars are expected to get an S55 3.0-liter inline-six engine developing 415 hp (310 kW), which would be just about the same as the current M3 with its 3.0-liter inline-six multi-turbo S55 pumping out 414 hp (309 kW). However, torque figure will be increased by about 100 lb-ft (135 Nm), reaching somewhere around 395 lb-ft (535 Nm).
The new M3 is expected to go on a diet to lower its curb weight to 3,415 lbs (1,549 kg), making it considerably lighter than the M3 E90 (3,726 lbs) and the M3 E92 (3,704 lbs).
The next-generation BMW M3 will be launched late this year or in early 2014, before going on sale in June 2014, while the M4 Coupe won't be out until late 2014.
Note: BMW M4 Coupe Concept render pictured