1. If you track, you need to log actively. Doesn't matter whether it is through JB4 or Cobb or MHD. Many things can cause a limp mode, and not all are heat related. But having a log and ability to pull codes, you can figure out what's the problem pretty easily. If you got a used car with decent amount of miles on it, it might be good idea to check the health of the your fuel system through a log and replace your spark plugs and coils.
2. Upgrading the oil cooler alone only solve half of the problem. CSF makes radiators for both AT and MT cars now (N54 and N55 uses the same radiator). They make a huge difference on track, and work even better with aftermarket oil cooler and PPK stage 2 auxiliary radiator.
3. Factory limp mode doesn't get triggered until oil temp hit above 300F (not that is a good thing though). Most of you guys are experiencing coolant temp overheat. That's why you need to upgrade the radiator as well.
4. All N54 and N55 will overheat eventually with stock cooling setup. If you haven't experienced one yet, means you are not driving it fast enough
5. I seriously recommend switching using JB4 as a boost controller and MHD as a backend flash for any N54 track car. Much easier to isolate tuning issues and you can make adjustment on the fly with a smartphone in regard to your wastegate duty cycle and fuel trims without dragging a computer with you.