IMH_ED_SPAM is peculiar to InMotion Hosting. It causes a lot of false positives for me too.
Their support advised: "IMH_ED_SPAM is a InMotion Hosting rule that matches known spammy keywords and assigns a spam score to them. The phrases in the list are common spam phrases that are likely to be blocked in other places. I would do a google search for common spam phrases and make sure that your newsletter doesn't contain any. I hope this information is helpful." -- Sent from: http://spamassassin.1065346.n5.nabble.com/SpamAssassin-Users-f3.html
