Maybe I should elaborate. What I meant was do you only drop power or only add weight (if enough can be added to drop to N300) or is there some optimal mix of both? Also is upgrading the engine with mileage points and detuning optimal for the power band? Or does BOP actually nullify any advantage that might be gained from an "optimal detuned power band"? I don't recall the BOP screen showing up but I might have another look tonight and stop looking for excuses as to why I haven't gone sub 2:00 yetYou can't tune it, you just have to make sure the power meets the N300 requirements, and BOP does the rest. When you join the "free practice" session you will have to choose a car. All the N300 cars show up on top, but all the cars that can be modified to meet N300 requirements are listed below and highlighted. If you select one of those it will prompt you to change the settings accordingly. In some cases you will have to use XP to "upgrade" the power options, which will actually give you the choice to tune down rather than up. I think with the SFR, as soon as you go below 300hp the red message at the bottom of the screen goes away. Once you select that power, BOP actually adjusts it to something like 247HP and fixes the weight how it wants. After that, nothing else can be changed except for TCS and Brake Balance.