Having reviewed this topic:
I would like to add that the current spool rate for jet engines appears not to be adjustable (at least, I have not found a way!) . In FSX, this was achieved by manipulating the N2 v FF table, but as noted in the above topic if you set that to adjustable ( '=1') in MSFS and make any adjustments, the engine fails to work entirely.
If we use '=0' for that table, the spool rate is reversed in comparison to a normal jet engine behaviour - currently it is highly responsive in the low RPM range and slow to respond in the high RPM range. A real jet has the higher responsiveness in the higher band's of RPM, hence military aircraft often use airbrakes and higher power settings in formation or in the circuit. Also, given that different jets can have vastly different ranges from idle to max, and thus different bands of responsiveness, it would be really useful not only to have this corrected in the default jet engine model but also to have an adjustable table that we can use to refine an individual engine's behaviour.