A generic spring compressor (long bolt with a threaded hook at one end and a slip fit hook at the other) will suffice. Be aware that the B4 spring diameter may not accomodate a compressor designed for a larger diameter spring. My JCWhimpy compressors work, but I can only get one hook of each pair on the coil loops.
Consider replacing the rubber cup in which the ball bearing is set. The rubber compresses over time. Look under the hood at the top of the strut assembly. If there is more than 1/2 inch gap between the inner fender and the outer edge of the metal cup, then replace the rubber strut top mount.
Springs generally don't need to be replaced. Measure the car body from some point to the ground. The back edge of the front wheel opening is a good location. Compare one side to the other. If less than 1/4 inch difference, then leave the springs alone. If more, check the gap difference at the strut top mount. The springs may be OK and the ride height difference may be the unequal degradation of the top mounts.