I agree with you on the ZF8 transmission. While probably not as fast as a DCT, it may be a better candidate for a swap: they're in so many cars, probably better at low speeds (less jerkiness), cheaper with more available parts, and can handle plenty of torque.Forget dtc, I would love to see a zf8, that trans has the gearing to .make lag obsolete, and will take what ever you throw at it. The trans controller will work with this trans too. I really want to do one for my sc300 build, but have no time to so it and no desire to pay someone to learn on my dime.
When the current (F90) generation M5 switched to the ZF8 from a DCT, it signaled there was no real major benefits to the DCT.