Haven't tried the KW transmission additive, but have heard of some success stories with it being used, particularly before a transmission pan drop/flush, etc...helps dissolve any possible build up that may be in the tranny supposidely.
Seems very similar to that of the Seafoam product, TransTune.
As far as MMO, I've been a believe since I revived this old 88 Dodge Aries, bought it from the stereotypical "little old lady" that barely drove it, primarily a grocery getter to the corner store and back, and church on sundays. When I purchased it, there happened to be a Mopar Parts and Service "Next Oil Service" sticker in the windshield still, slightly faded, but from what it said, it was due at ~29k.....when I drove it out of her drive way it had ~27k on the clock
I poured about a tsp of MMO into each cylinder (through the spark plug hole), about a half-pint into the crankcase (the dipstick read a little low......BUT no leaks were seen.....so perhaps they just didn't completely fill it when she had it serviced? Who knows...), and the rest went into the gas tank. The beast fired right up
Only complications I've had thus far, had to changed out the coolant temp sensor, and the coolant sending unit, and thermostat (apparantly, someone completely removed it! hmmmmmm....) lol. And about a month ago I let my mechanic take a look at it, and he said everything looked great, body is in great shape, the under-carriage/body is near immaculate too. He couldn't believe it when I read the mileage off to him
It did have a rough idle, but that was due to some dried out and broken vacuum lines, but that was an easy fix-up, and it's running great.