Yeah the OG HE6 slams with more weight, but the bass of the Susvara and HE6SE are about the same. I recommend to give my passport mod a try. The bass will roll off at 25Hz but you get more movement of the diaphragm.They seem to pair extremely well with my system. I am digging back into the HE-6 thread now, obviously, and have read on numerous posts/reviews that the OG HE-6 has more bass slam/content. I am listening to 'Drums of the World: Globally influenced percussion' and some tracks are bordering on uncomfortable levels of bass impact and slam. Feels & sounds like I am sitting next to the drummer. The diaphragm is visibly moving a fair bit - more than this would be too much. Amazingly accurate/ruthlessly aggressive planars!
BTW, depending on your listening levels, if it is really loud with a lot off bass, don't remove the HE6 from your head before turning the volume down, one observe the moving diaphragm at lowest possible volume. They can get stuck to the magnets... My horror story and first bassport post: https://www.head-fi.org/threads/hifiman-he6-se.886229/post-16367236