The Cummins 6.7 ISB unit (250bhp) has been good though over recent years.

And I believe the examples used on the X93 were shot after Blyth got their hands on them first whereas Ashington's original batch were fine bar 7510.

If anything, the E400 & E400MMC has become more "heavy duty" over recent years in comparison to the B5TL & StreetDeck.