I finally ordered a new Shimano M131 crankset and BB-UN55 bottom bracket to replace the wobbling junk that came stock on my wife's BikesDirect bike. The chain rings were wobbling such that the chain would move back and forth and rub one or sometimes even both FD plates.
Took everything off, and HOLY CRAP the old forged steel crank arms were beastly! The old crankset weighed in at 1,680 grams! The new Shimano crankset with aluminum crank arms and similar riveted steel chain rings came in at just 1,073 grams! That's a difference of 607g or 1.34 pounds for a mere $25!
The Shimano BB ended up being 310g vs. the original's 307, but it has a metal left side adapter cup vs. the original one being plastic. Also the original is a "Chia Haur" BB which I read has had a history of issues including catastrophic failure. So I'm glad I got that thing out of there.