The space bar plasticky noises can be quieted or eliminated by greasing the stabilizer;s contact points - both the bar's and the board's. A little dab of white lithium grease it all it takes, and it helps quite a bit.
My keyboard has one-piece keys, so I don't get the wobble or any noise from separate keycaps, but I get plenty of spring noise when keys return to rest. I've tried the Superfloss mod, and 14-15mm of floss in each spring does eliminate that, while leaving the click as the spring buckles. I found the floss on sale, 2 packs for $6, and white lithium grease is as cheap as they come, so you should be able to quiet things down for very little money, and maybe a couple hours for the flossing.