removed and included in my tune

 

I decided to replace it. after three weeks I am convinced it had a negative effect on my performance. Gas mileage went down and the car didnt seem to pull as hard when getting on it. So after three weeks of getting used to how the car felt without it - I put it back in. I noticed an improvement immediately, the car responded better when getting on it in all gears.
I now completely agree with those that have suggested if you remove it - you should really get a tune. The car was designed with it in mind.

 

When I removed mine I noticed that breaking traction in first gear seemed very easy with normal throttle. (traction control still on) My avg gas mileage went from 17.4 to 14.3. Significant mpg loss so I put it back in. My mpg is still in the 14+ but I have been doing all local roads driving. I think I may need a reflash if the mpg does not improve over the next several tanks of gas.