Hi!
Great read by the way
You could try one thing: remove the green filters that sit in the nozzle and try replacing them with some porous foam. Me, as well as other members, got the best results by letting the metal part of the filter in the nozzle, but I would advise you not to break the filter in the first instance, so that if you don't like the sound, you can still go back. If you simply remove the filters and do not put any foam in the nozzle, the sound will be harsh, however.
The filter mod, discovered by me and improved by dweaver, will bring the upper mids forward (around 4-5 khz) and as you'll have to reduce the overall volume to get a comfortable volume, the bass will be slightly lowered as well. I think it's exactly what you are looking for, no need to buy new iems
For the mod, search through this thread, I posted a picture of the filter removed and explained how to remove it.
You can read my impressions here:
http://www.head-fi.org/forum/thread/504607/the-all-new-earsonics-sm3-appreciation-discussion-and-review-thread/1020#post_6898936
http://www.head-fi.org/forum/thread/504607/the-all-new-earsonics-sm3-appreciation-discussion-and-review-thread/1080#post_6903131
My second impressions are not as good as the first, but I finally found a golden medium, with the metal part of the filter in the nozzle with some porous foam (you have to fiddle a bit to find the right amount of foam you need).