Do you have the instructions? You dont really have to remove them, but it may be easier that way. You wont have to fight the pressure or the strut to bolt down the plates that way. In any case you will have to take the top nut loose. Sometimes its best to use an impact wrench for this. I was replacing my worn out ones at the same time, so I used vice grips to keep the strut shaft from turning.
Dont align the front end yourself. You may get the toe and camber close, but you wont get the camber right at all. Dont tell them the car is lowered. Just keep checking around, you will find someone to do it. I wont give anyone the keys anymore. I tell them that I will drive it on and off the rack and do the test driving or they wont work on my car. Alot of shops will tell you to get lost when you tell them that, and I found a shop to do mine.
I also recommend flat washers above and below the plates, in addition to washers on top of the strut tower. I have to take mine back apart to do this. For good installation instructions go to www. maximummotorsports.com, click on instructions and choose the CC plates. The install is the same in general for all brands. Or try the bbk site for instructions. Have fun.