Thanks guys, sorry I haven't visited the forum for a while. I did check my chargepipe and it looked ok, but I wasn't sure if there is a leak or something. I assumed this since it only happened in high RPM/high load. I will check the codes this weekend, I have been a little busy lately...
From the comments I understand that it's quite unlikely to be the chargepipe, so that's a good thing
It's interesting to know about the spark plugs, but I only have 26000km, so is it still possible?
I hope it's not the HPFP.. I have ruff cold starts, I need to let the car idle for like 5-10s when it's been parked outside in the cold, otherwise it would stall.
I think I may take out the JB4 for the winter, no need for that extra power on the snow, so at least I can compare with/without.