Well of course they would they want a sale, they're not going to tell you a product they sell has no real effect.
My inlets were matched by Jam Sport too, i'm not slagging them off or anything, they were really nice blokes, they may even have rolling road printout that show a few bhp improvement, it's just in terms of power you won't notice a damn thing on RS inlets.
The 3 best mods on these cars for improving/optimising power are the K-Tec style induction kit, a decent 2.5 inch stainless steel exhaust and a remap by a good tuner, after that you'll have to spend big money to get more bhp.