It's all in relation to the overall combo.
Slap a base model, out of the box Performer on an otherwise stock engine and you might gain 10-20 hp, take that same intake and do a cam swap to match the power band, you might gain 75.
The performer intake was designed to be a slight upgrade to a stock, key word slight. No when you start getting into Airgaps, Holley street doms and others, that's where you'll start seeing more difference, especially if the combo all matches each other.
I will agree that mopar factory intakes weren't too shabby in their days, neither was that big TQ, by pass all the emissions stuff and you had you an 880 cfm carb with massive secondaries
