no reason to do 4 wheel discs unless you are gonna get massive on the tires or if you are insane about your brakes.
you'd need all the brake parts, a new MC, new proportioning valve, new rear lines most likely.
If you have no boost....i'd check your booster. Is the vac line hooked up? check valve good? If the diaphragm inside the booster is gone you'd have a vacuum leak and the vehicle wouldnt run well. When that happened to me I still had boost but it cause it to idle poorly only when I was on the brakes.