Top performance for a normal 1.7 liters DA-40 TDI, according to the POH is 140.5 knots TAS at 6000 feet PA, on just 7.7 USG/hr (ISA, MTOW).
As always with POHs more than a tad optomistic in my experience! Moreover the load carrying and take off performance is not there, albeit that can only improve with the new 2.0L engine - perhaps quite significantly.
The 42 will also be so fitted and will compete with every SEP but with fuel burns of less with two engines and the price advantage of A1.