Cuda rear valances.. Stay away...certain brands?

[FSHTAIL]

I see Goodmark lists 2 rear lower valances.
With and w/o exhaust holes.    But from 70-74..   

AMD seems to have both versions, but different part numbers for a 70, 71-72, 73-74.. 

Is a 74 rear lower valance different in regards to bumperette provisions vs a 70?

Can someone point me straight on what's what on these and if there are any brands to steer clear?

AAR's simply used a non exhaust style valance, correct?

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