Hello Adam,
Are you setting the firepower recommended rules automatically to install/download?
Normally when you manually run the recommendations, there is an option to only generate the recommendations, a "looking glass" would show after they are generate so you can see the changes between what you had and the new state. After reviewing, you can choose to apply them.
If they are automatically applied/ you have a task for it, then I do not know of a way to see the changes.
But, if you are seeing drops in your traffic, and it is the new IPS Policy, you should see an IPS/Connection event.
Analysis > Intrusion > Events
The value within the parenthesis, the first number, is the SID rule.
If you need help to identify the rule that might be causing the issue, you can always open a TAC SR to help you identify and modify your rule.