first time go at it I'd give yourself 4-5 hours. Balljoints we're £30 from my local meccy/factors, don't know about fitment cost though. Probably only a couple of hours for someone that's done it a few times. A standard socket set should be enough as long as the grub screws on the discs are free enough, but that's really helped by an impact driver, as you say. The old joints take some serious smacking to get out but they will come; perseverence & faith definitely required!