Its it just me or does the WRX slow down after a while of owning it. I put the VF34 on and it went fast

I put an ECUTek on and that seemed to slow it down, not according to the tuner though.

So I looked harder at the car and yes I was forced to believe the tuner, it was faster (still believe it to be slower, dont tell the tuner)

So after a couple of weeks the car just doesnt feel fast anymore.

Is the car slowing down or is it just the bug biting and telling me to mod it some more.

Come to think of it I should have just gone a STI