Well firstly, the E46 320 is a 6 cylinder and the E90 320 is a 4 pot - same badge different sounds

. If you do a search you will find that the E46 320 actually is not really value for money, rather go for a 325 or 330 as the fuel consumption is almost the same. The E90 320 is a good basic every day car, but under powered especially in auto. Rather suggested a 323 or 325 in that range.
IMO R150k is definitely E90 money, you could easily find a 320d or 325 ! Good luck with your search