Excused the burden of objective comparison, the Infiniti M30d would score near full marks in this section, because its diesel engine delivers more than sufficient performance for almost all everyday situations, yet it is also suitably refined for an executive saloon.
This 235bhp, 405lb ft 3.0-litre V6 is a mighty first effort (with a little help from Renault), but that doesn’t change the fact that the M is stepping into a market packed full of talent.
We simply cannot forget the existence of BMW’s 530d, Mercedes’ E350 CDI and Jaguar’s XF 3.0D S. For the price of the diesel, it doesn’t compete hard enough in terms of outright performance – rivals are simply much quicker.
Similarly, those who have never experienced the competition would have little complaint with the M30d’s seven-speed automatic transmission; its changes, for the most part, are smooth and well timed. But when you have experienced those rivals, notably the BMW, the Infiniti feels just slightly second best.
The M35h hybrid is much more interesting (especially to company buyers) with a potential combined power of 359bhp and 457lb ft of torque give it a 155mph top speed and a 0-62mph sprint of 5.5 sec, while returning an impressive 40.9mpg combined with official CO2 emissions of just 159g/km.
The diesel can manage only 37.7mpg and 199g/km, and its performance isn’t in the same league as the hybrid because it has just 235bhp to work with.
The 3.7-litre petrol M37 is extremely quick-witted, agile and thrusting, making good use of the motor’s sweet-spinning and pacey nature. The M37 also feels firmly planted and stable at high speeds.
However, if you’re tempted by the Infiniti as an alternative choice (as we are), the diesel’s relative lack of performance shouldn’t put you off. Especially as in other respects – such as refinement (engine and wind) and braking performance – the M30d has nothing to fear from the competition.