I just decided to mix things up and take my AspEx to a fight (for the first time).
I ended up having to run away because it was sooo different to my Vulture.
I had used Coriolis to spec it out and ensure that it wasn't too horribly compromised wrt my Vulture. So it had better DPS but somewhat weaker hull and shields. I had checked the agility figures and they were slightly worse than the Vulture but not enormously so.
However, in combat, once I diverted pips to shields and weapons... OMG the AspEx was a total pig.
I then went back to Coriolis to see if I had had some kind of brain fart while comparing the specs, and no. But when I varied the ENG pips within Coriolis, the effect on the Vulture pitch rate was negligible and the effect on the AspEx was massive.
I haven't yet drilled down into the data underneath the Coriolis calcs (but given my experience the results seem plausible) but I did a bit of Googling instead. I found a thread here (locked tho) at https://forums.frontier.co.uk/showthread.php/367675-Engine-pips which @Morbad refers to the Vulture as being affected in a "subtle" way by ENG pips while others are more extreme (e.g. Python).
Is there a comprehensive list anywhere of how ships are affected by this?
Another, slightly more exotic question: how on earth can this behaviour be "explained"? The two ships in question both have 5A Thrusters and fairly similar mass (tho fair enough, the AspEx has a lower class PD).
Asp hull is about a third more massive, w/ Vulture at 230t and the Asp 60t more.
Built similarly in combat fit, the Vulture clocks in around 450t, with the Asp about 140t more.
So just in mass it's a pretty significant difference.