The longest part is copying your original stock tune onto the PROCAL...estimated time was about 45 min for me. Once you download the FPP tune from laptop/pc to PROCAL and flash ecu estimated time was 15-20 min. So I agree with the recommendation to charge battery for the process.Mine finally came. I was confused by the instructions but in the process of summarizing the steps to format some questions to ask here I understood it. I got mine from the dealer so I could use my "points" and will take the programmed tool and my truck in and essentially have them do the last step(s) so as to gain the warranty. I negotiated a reasonable labor charge and am looking forward to getting it "installed" next week. I plan to use the K/N for now but will add the Roush CAI in a couple months. The instructions seem to warn about having a fully charged battery as if the process took so long it could cause problems. It made me wonder....wife's Honda will only stay in accessory mode so long and then it automatically shuts off. Is this something to worry about as the instructions warn "IT IS HIGHLY RECOMMENDED TO CONNECT VEHICLE TO A BATTERY CHARGER/TENDER TO ENSURE ADEQUATE BATTERY VOLTAGE DURING CALIBRATION PROCESS"