Fundamental aspects of transport in Al ion implanted p-type 4H-SiC are briefly reviewed, in the light of recent literature. Particular attention is paid on (i) the Hall factor and (ii) the role of disorder in the onset of a variable range hopping mechanism (VRH) at high temperatures as doping level increases, up to a 2D-VRH induced by extended defects in the heaviest doped samples. The study allowed to understand the critical balance between implanted impurity density and annealing temperature that leads to the searched doping level, ensuring an efficient electrical activation of implanted impurities, on a side, and, on the other side, avoiding stacking faults that cause anisotropic hopping transport.