For the 5525-X, you would use identical part numbers. Each would need an associated Smartnet support contract for their respective IPS modules' subscription-based definitions to update properly. All the other licensing on the Primary - Active unit would convey to the Secondary - Standby in an HA configuration.
Although you didn't ask, if you had the 5512-X entry level model (or older 5505 or 5510) each would need to be ordered with Security Plus licensing to build an HA pair.
I would recommend considering either the FirePOWER or CX module IPS vs the one you mentioned. The ASA5525-IPS-K9 is the legacy Cisco IPS technology that's gradually being phased out in favor of the newer type. While it is indeed still sold, we are encouraging customers to consider adopting the Next Generation Firewall IPS type vs the older one as it covers a more comprehensive threat spectrum.