What's wild to me, every other industry on earth trusts Facebook's catalog advertising algorithm to just work and do it's thing.
Only in automotive, would we be like "oh hey...you're matching these items in my catalog too frequently to shoppers and not these items enough" and then proceed to break the algorithm by reducing the catalog (which is what this does).
Imagine Target putting a click limiter on certain SKU's because Facebook was driving too much traffic to them...
I have seen instances where certain "eye-candy" vehicles capture a lion's share of the clicks when dealers run a single AIA campaign for their entire catalog and are optimizing for content views or clicks, so it is certainly something to be cognizant of.
We run a variety of AIA campaigns - some for the entire catalog, others for segmented vehicle sets. This ensures we still have a level of control over where our AIA budget goes.
For new cars, we typically create sets for each model and then the body style category. For used cars, we will create sets for different price ranges, body styles, inventory age, CPO, etc. This strategy also allows us to tailor the ad copy and creative to each set's typical buyer persona, all while being able to direct the budget according to our objectives.
And it doesn't hurt to create catalog filters to exclude specific vehicle models (high ends sports cars) or vehicle years (classic cars) that don't need the traffic yet tend to receive a lot of it.