I don't have any recommendation on the legs. Whatever you can afford I guess. I'm pretty happy with the Sirui legs I bought although I admit that I haven't really given them a workout yet. On the head... well, I've never had much luck with tilt/pan heads. I've always found a ball head easier to work even if using one does mean that you have to pay attention to what you're doing more than you would with a tilt/pan setup. However, if I were shooting what you usually shoot... namely, sports and action, I would give serious consideration to a gimbal head. I don't have any experience with one but if I had big lenses like you use I would definitely consider one.
Here is a short video from B&H that features the Sirui gimbal head. I'm not shilling for Sirui ... I just happened to see it. I'm sure other makers such as Really Right Stuff have much nicer versions.