We propose an iterative receiver for horizontally encoded MIMO systems like the PARC proposal for MIMO-HSDPA. Our receiver uses a K-best-MAP demodulator to provide the channel decoder with approximate log-likelihood ratios. The complexity of K-best-MAP is reduced by exploiting the CRC present in each encoded layer. We show that K-best-MAP with list update is superior to demodulation using a fixed candidate list. Finally, our numerical results demonstrate significant SNR gains as compared to a receiver using MMSE-based successive interference cancelation.