(This is a question for Charlie, but ALL should feel free to contribute!)
Charlie,
I have been working steadily on my squat since september, I can now do 180 kg half squat for 2-3 with a body weight of 75 kg. Do you think that I would benefit from using a variety of squat techniques, such as box, full and partial also?
Did any of your athletes use suits or knee wraps when squatting, would you recommend such measures ?
im not charlie or a sprinter, im a powerlifter, and i dont think you would get a benefit from using a suit.
Just my opinion
Knee wraps?
Knee wraps?
Do you run with knee wraps?
…and a squat suit 
no knee wraps either
Martyn76, utilizing all forms of squatting will benefit you tremendously.
Additionally, box squats accomplish what no other form of squatting can accomplish-this is breaking up the eccentric/concentric chain, thus allowing for a static/relaxed overcome by dynamic contraction. Pause squatting is not the equivalent of box squatting.
Box squatting is tremendous for developing explosive, starting, and reactive strength to name a few. And you may squat at any depth you wish with any size box.
Also by utilizing a very wide stance box squat you will greatly strengthen your hips. Building up a strong wide stance squat will allow you to squat with more weight with a narrower stance. NOT Vice Versa.
Furthermore, squatting on a box allows you to sit back much further than you can without the box. This develops the low back/glutes/hamstrings much more than squatting without a box. And as you must know, the muscles of the posterior chain are your powerplant for sprinting. The quadriceps group is highly active at the start-first 10m or so after which an upright posture is achieved where the posterior chain plays a much larger role.
If you perform wide stance squats you should wear a suit with the straps down or groove briefs. This will protect your hips/groin. This holds true for all athletes, not just powerlifters.
Full squats stimulate the quadriceps/hamstrings/glutes to a greater degree than half squats. And again, the more you can full squat the more you will be able to half squat, NOT Vice Versa.
So as you can see you would be wise to incorporate all forms of squatting into your program.
There is no need for knee wraps on any form of squatting while in training. And the only need for a suit is when utilizing a very wide stance either on a box or free standing, and in neither instance do you need to have the straps up.
James