I have a panel filter and the Revo intake pipe on my CS and I can tell the difference (standard tune) - it just feels more responsive but not sure there is any additional power, the turbo just responds more quickly.
I bought the Racingline elbow but sent it back as there is no smooth transition where the elbow meets the turbo and the seals were terrible - perhaps I had a dud. I would recommend the integrated pipe with machined end which fixes to the Turbo. A few companies make them e.g. Forge, Revo & Turbo Technics.