Don't do it. You're more or less "tricking" the ecu, and it can and will relearn around it. The closest I've seen someone came to tuning the YF is PowerAxel. I think someone had a tune up to 300whp but there were some issues.
Not that this has anything to do with your car but... a friend had a BMW 135. Got a chip, plus exhaust (minus cat), intake filter to make the whole package work. Just a chip wouldn't necessarily do all that you want. And when the turbo failed he had to put all the old parts back on to claim warranty! But it was the fastest 135 in the world at that time. Since then better chips have been made.
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