authority is pretty good.
but ive had my ecu remapped by powerchip.
The hp gains are defiantely noticable. Although they will vary depending on the ocatane number of the fuel you use.
I paid around $600 for this.
And now im always finding excuses to get behind the wheel.
Before this honestly the car got annoying bcz im convinced the e90 325 has no response till 2k rpm.( throttle problems)