I would be curious to see a poll of how many people who are seriously considering building an 818 would want the option for the 6 speed. Personally I wouldn't and I can't imagine too many people would. It seems like a small window of people who want something more robust than a stock 5 speed, but are not willing to pay for a built 5 speed, but are willing to take the weight penalty, and source a 6 speed from a separate donor when they presumably already have a 5 speed from their donor WRX. My point is that there would've been little benefit to FF from modifying the design to fit a 6 speed. They might have considered it at some point and ran into some other issues, and decided it isn't worth it. Maybe it sucks for some people who just really want a 6 speed, but that can't be too many people. 75lbs is a lot of extra weight in this car for no benefit. A 5 speed with PPG gears would hold up just fine. If you are spending the money to get a high power build anyways, it should be an obvious upgrade.