Clarification of the contrast resolution (CR) and spatial resolution (SR) limits of phase based MREPT for conductivity imaging is essential for assessing its success success in clinical applications. Noise analysis of conventional phase based MREPT is performed to find the SNR needed for the MR sequence used for measuring B1-phase. It is found that with 1000-2000 SNR values about 0.01 S/m CR can be achieved. For SR evaluation, generalized phase based MREPT, which does not suffer from internal boundary artefacts, is considered. It is found by phantom experiments that 3.5mm spatial resolution is easily obtained with the state-of-art MR methods.