Weighing in at just 1.5 tonnes, the latest dream performance M cars from BMW are a reality. Motors went to the Austrian Alps to put the performance cars through their paces, on some of Europe's most challenging roads.

M Sport cars are more than BMWs with big engines (although the engines help): they are machines created by obsessive car nerds that simply love their work. The latest M3 (five-door) and M4 (Coupé) have been completely rebuilt from the ground up with a sprinkle of BMW's M division's fairy dust. The result is two hugely entertaining cars. Obsessive attention to detail really sums up what M cars are all about.  

Performance is up on the outgoing M3 despite the loss of two cylinders - down from eight to six - but the four tailpipes remain. There was no 4 series back then, just a saloon and coupé version of the 3 Series. The bi-turbo (a turbo on each bank of three cylinders), three-litre petrol engine pushes out 431hp and a whopping and magical 550nm of torque across a very broad rev range. 

Manual and automated-manual (M Double-Clutch Transmission) gearboxes are available, with the auto expected to be the big seller. It also delivers the fastest sprint times with 0-100kph taking 4.1 seconds! In-gear performance has taken a massive step forward thanks to all that torque. 

Like the M5, you can tune the M3 and M4 to suit your driving style. In normal mode you can tootle along without any drama and feel like you're in a normal car; but if you press the M1 or M2 steering wheel buttons you can really have a ball. 

These programmable little buttons let you precisely adjust a number of things that affect the performance of the car. You can adjust the stiffness of the 'adaptive suspension' (that is standard on Irish cars) or the gear change speed. You can also adjust the engine response, steering weight and power output and, of course, the amount of electronic driving aids and the degree to which they can intercede. 

Basically, I set up M1 to deliver a sporty driving experience and M2 to let me fully explore the car's performance potential - again, a setting that's not for the fainthearted on alpine passes but thrilling nonetheless. 

Our test cars were fitted with optional ceramic brakes that worked endlessly without any fade on roads that could have cooked conventional brakes. That's a very expensive but valuable option, especially for sporty drivers. We've said it before: a performance car is only as good as its brakes.

Now don't laugh, but M3 and M4 are pretty green. They benefit from fuel-saving technologies like auto stop/start. This means you can get pretty good fuel economy - again, saving the planet is not really going to be a priority but they're trying. Prices start at €100,050 (M3 OTR) or €100,890 (M4 OTR).

M3 is practical but will sell in fewer numbers than the very sexy M4 Coupé. Yes, the asking price is high but the car is outrageously good. If you enjoy driving M3 and M4 will exceed your expectations - both are simply brilliant!  

Michael Sheridan