That sounds like alignment, especially at the speed you mentioned. That is the #1 symptom that your wheels are misaligned. It is one thing to balance the wheels, another to make sure they're straight and level. Another warning bell is that you adjusted the height. You need to be sure that it is aligned.
A second scenario is that you did not do the alignment immediately after adjusting the suspension, and then proceded to cause uneven wear on your tires. So you get the alignment done, but you're still driving uneven tires. So check the tires themselves. Get a ruler or something and measure the tread depth on the outside and inside of all 4 wheels and see if they are the same.
You didn't say how it is shaking, but if you notice it in the steering wheel especially, a very likely cause is uneven tires on the pavement. You may also be able to hear it (if music/radio is not on), especially when you are slowing down with the car in neutral. Whether this is because of alignment or unevenly worn tires is to be determined...