Torque is more important on a diesel than bhp, of which the 30d has a maximum torque of 670Nm of and 0-62 in 6.1s.
The 40d a maximim torque of 720Nm and 0-62 in 5.5s
In the real world, there is not much seperating them and the 30d mild hybrid has become more powerful than the 40d no hybrid generation.
The earlier late 22/23 years alo also mild hybrid and apart from the letter code engine specs remain the same, with the electric motor producing 200Nm of the torque available.
