Firstly Economics Honours required an in-depth study of Economics whereas the IPM program focuses on the many areas of Management. There is a drastic difference between the nature of both courses. No doubt Economics knowledge is beneficial for the IPM program but is not necessarily important. In IPM, Economics is just a 4 credit course in a term of about 30 credits.
IPM hugely emphasizes Quants over Economics. So if you are more interested in Economics, then IPM is not for you. Your choice should be a good college from DU North Campus. If you manage to get into one then pursuing Economic Honors is a much-preferred option over IPM. Don’t choose a below-average college for Economic Honors. In that case, go for IPM only.