Still pretty much impossible to diagnose with that amount of info. I guess more questions is was this something that gradually got worse or was a sudden onset? Does it pull right or left when brake? Is CEL on?... I know a somewhat sudden onset of shaking and bad performance and pulling when braking, could be, like I had a few weeks ago, a stuck caliper.
I got nothing from this "DIY"... Where are the pics?
But anyways, if it is driveline related (don't know without more info), my guess would be a CV joint on one of your front halfshafts is going, or one of your universal joints on one of your main driveshafts is starting to bind slightly. A vibration/shaking under load at lower speeds is the 1st symptom of these kinda issues. Both are expensive, but the driveshaft u-joint issue is by far the more expensive/pain in the nuts ordeal.
If you want more better help, try moving this thread to the 'general' forum where the experienced people will be more willing to help ya out.
Check your tires - be honest, have you put off replacing low thread tires? if so, this can and has caused steering wheel shake.
I put off replacing mine till I was able to replace all 4 at once with Continental Tires ExtremeContact DWS from TireRack. I thought I had worn suspension and steering components but after the new tires the car felt like new when I left Mr. Tire.
Next check the condition of the rubber mounts as others suggested.
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