I must admit after a few weeks I was a little paranoid about losing power too. I started with a td04 at 200hp and jumped to 325hp the next tuning session. After a couple of weeks a sneaky vacuum hose popped off which took a while to find, then when it was all back to normal I feared I had lost power as the pull didn't seem to hit me as hard.

But it was really me just having adjusted to the new power. I went to the drag strip again and matched my speeds from the previous visit so all was fine. When I started taking it to race tracks I was very satisfied with the power I had. It's just pulls in a straight line that you tend to get used to.

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MY08 WRX 325hp/456nm/18psi E85