they all effect your lipids, even aromasin, some more than others, and in differnt ways. i wouldnt worry about until you got to half the dose that studies have found that it causes an issue.
for instance, arimadex effects total triglycerides (in women) at 1mg ED. keep in mind these studies were for like 24 months. it was reported to have an impact that barely increased your chance of CVD.
the other problem is that AI's, more than other subtances, have quite a different impact in men than they do in women. so dont get me wrong i wouldnt want to run adex @ say 3mg a week for super long periods. if i had to for 6 months I wouldnt worry about it. but there is no reason to run such a high amount for so long, cause you can usually find other ways to control estrogen so that you dont need that much. Like eating anti-estrogenic foods, lowering BF%, staying away from foods that have high estrogen response, increasing injection frequency...........the are more but cant remember right now.
that make sense?
now with letro everyone says how harsh it is. and it will effect lipids, but studies show this @ 2.5mg ED in women. in most cases .625mg E3D is plenty. I think cholesterol effects are dose and duration dependent. just as is the % of aromatase enzymes that are affected.