Onur, does it really surprise you people are willing to go out of there way to help you. In the pass you have helped me out several times and asked nothing in return, how much more unselfish can you get. All the positive karma you've put out to others is coming right back to you.
I trimmed the dashboard with my Dremal, easy and very effective. Make sure you unplug the stock amp which is located in the back of the glove compartment. The plugs only fit one way so you won't be able to install the wrong one.
First off never drive it on paved road while the lockers are engaged, I'd much rather pay for a tow than f'up my lockers. The lockers not engaging is a common problem, due to lack of use. Due a search on lockers not engaging and you'll find tons of threads stating your exact same problem.
You shouldn't have any brake issues, we didn't crimp or damaged any brake lines that I saw. I told you as you start loading up on armour you would feel it.