I mean this with the upmost respect but did people honestly think it would help cool the oil? How would anyone look at those fins and think it would cool the oil anything noticeably? If oil cooling caps were an actual thing other platforms would have them. It's just not enough surface area in an area with poor airflow. It's just going to make for a VERY HOT oil cap when you go to take it off. Usually people drain their oil when it is warm to get a good full drain. So now when you do it you need oven mitts to hold the oil cap as it is metal and the 230 degree oil will conduct it's heat VERY well into the aluminium. It is also touching the metal on the engine too right? When fully compressed/seated & with the threads? It would be impossible to cool the engine block down with a few metal fins on the oil cap."I'm all for improving factory designed stuff but it's an oil cap. If it seals well and does not leak it's doing it's job."
The theory behind the fins and aluminum design was lower oil temperatures... obviously that did not fulfill its designed function and now the community knows because folks went out and tried it for a long period. Anyone can make a cap that doesn't leak. If people bought the new design thinking it would be better at not leaking, then obviously they missed the point and wasted their money.
Only reason I can see using this was what was explained above because the stock BMW 'tool' for removing the oil filter housing will no longer fit well with certain aftermarket intake manifolds. I would still argue to just use a different oil filter wrench and be done with it vs. spending $65 bucks. Or just modify the stock tool so it will fit with a hacksaw if there is only one area with a clearance issue.