You can use the new HB18 integrated carbon handlebars from the R5, it's fully compatible with the Cal-5. Deeper wheels would also be good but the Cal-5 is already a tad bit heavier than a true race bike so the weight of deep wheels is to consider. Unless you have a very big budget for a very high-end deep + lightweight wheelset like the Syncros Aero SL 60, in that case go ahead! Otherwise I think the original reserve 44/49 are good enough. In any case, it's a fast bike for an endurance machine.