When the integration with the current Spectrum OneClick configured as the Data Source in NetOps Portal is deleted, it will remove all Spectrum contributed Inventory, including Global Collections.
Also, as the IP domain containers will be removed from Spectrum, any rules on the IP Domain controllers will be lost. If you need these rules, you must record them before removing the Spectrum data source.
When the new one is added, it syncs all the Global Collections. Then it will create a Domain-based GC on Spectrum. Once that is populated, it'll sync the devices added to Performance Management.
If any of these devices are only coming into Performance Management from Spectrum and no other data source, if they are in Groups, those memberships will need to be reset.
If devices come from multiple data sources, like the Data Aggregator and Spectrum, the device will remain from the DA Data Source. The newly synced one from Spectrum will be consolidated with its match in Performance Management from the Data Aggregator. If that's the case, they should maintain existing group memberships.
The main impact is if you have NetOps Portal Group membership based on synced Spectrum Global Collection memberships via Group Rules. Those will lose the currently associated GC synced from the current Spectrum Data Source when it is removed. The new GCs synced from the new Spectrum OneClick need to be reset in those Group Rules if they are in use.