I have had the CRD3+ now for about a month or so with the pedal box, i run my tuning box in 2 +2 and the pedal box in 1 +2 and it delivers the power very smooth, much smoother than the old CRD2+ box. My MPG went up about 5MPG with the box attached and I have even had some warranty work done on the turbocharger pressure sensors since having the box installed. I guess that if something major was to go faulty the dealer might be less easy going about the tune, however the mechanic knows all of the changes i have made to the car and hasnt made any fuss about the warranty work its needed so far.