I don't see how you'd remove the stock springs without compressing them. However, it is possible to install the new springs without compressing them. Install the upper shock mount back on the body, then loosely bolt the spring/shock assembly to the lower control arm. Place a jack under the lower control arm and slowly jack it up while carefully guiding the shock shaft into the upper mount. The weight of the car will compress the spring, and you can put the washer and nut on the shock shaft once it pokes through the upper mount. You should always be careful when working with springs, but I don't think this method is dangerous, and I've done it a few times now.