Good news, everyone! The Tranzformer controller arrived recently and I installed it on Sunday. Installation is 6 screws and 8 wires, under an hour from start to finish.
I haven't had the chance to hook it up to the laptop Paul Walker-style to make adjustments while driving around (danger to manifold!) but even just using the stock settings is a massive improvement in shift quality. In normal Drive operation, shifts are firm and crisp and no longer vague and soft. Downshifts are hair harsher than I'd like but I'll dial those back a notch when I dig into the software. Autostick mode has gone from being slow, soft, and useless to grin-inducing fun - shifts are very quick and hard and there's no longer a squishy delay when you hit the shifter. I know I can dial shift strength up to chirp-the-tires hard but that seems excessive.
Being able to use the steering wheel volume controls to shift is almost as good as having flappy paddles - nice to shift while keeping both hands on the wheel.
One (fairly minor) annoyance with the vehicle I've run into (unrelated to the Tranzformer) is that the PCM's throttle management adaptives are pretty annoying. My commute involves a lot of octogenarian-style driving (having a live fuel economy readout is a curse), so the computer is pretty convinced that it's owned by an old person and maps the drive-by-wire to suit that. So naturally, when I do decide to romp on the thing, it goes "Gosh, Mildred, are you really sure you want that much throttle?" and there's a noticeable delay as the torque management system struggles to reconcile my previous hypermiling with my current need for speed. I really need to find a way to kill that system (the Tranzformer kills the transmission adaptives but can't mess with throttle adaptives) as I'm perfectly capable of managing my right foot without computer interference. There's a key-button-fuse trick I can do to reset things but that's a temporary measure. A couple of full-throttle launches seems to wake it back up but again, it eventually re-adapts.