The stock 12-strand wires come out of the motor assembly to the connector is about 8" long. I would extend the wires by at least three feet. I have three SP10's so I plan to do this soon. The important thing is that in the stock form, the motor is bolted to an 1/8" cast aluminum and the motor just hangs there. Now, imagine the motor mount directly to a thick slab of slate or wood or whatever material you like to use, don't you think that's better than the stock form? If you use the stock chassis, I don't care how wonderful your plinth will be your motor is still bolted to a thin sheet of aluminum hanging there. Just spend the time one day and carefully take the motor out of the stock chassis and then examine it yourself and you will know exactly what I am talking about. It's not rocket science. Almost ALL direct-drive can be improved this way. And for whatever reason, if you don't like the sound, just put it back to stock form - it's all reversible. The reason I haven't done it sooner is that I don't have the tools to cut slate! I would suggest keeping the stock chassis to house all the electronics because everything is all there with the buttons and switches, why re-invent the wheel? Unless it's an aesthetic issue and you just want to play around, go right ahead!
I plan to have two SP10 set up this way so I can have one tape-driving the other platter so it can be used as direct-drive and belt-drive. Fun!