I find they sound very full already. They aren't as thick as the SM3s, but they're still fairly thick sounding.
Play around with the different tips. Tbh, I don't think the cables will change much (and they're super expensive to boot).
If they sound less full/lively as in they kind of sound ... I dunno, deflated and muffly, consider taking out the filters in the spouts. I hated my SM64s and thought they sounded like crap when I first got them ... and then I took the dive because I was so upset and just pulled out the filters (like I did on my SM3s) and then it sounded like an actual high class IEM (was like a 100% difference).
But for IEMs, it's mainly an issue of tips... Try different materials too. Some tips are gooey, some of them have a hard, plastic core. I usually like the ones with the hard plastic cores better, but you might like gooey tips more (like double/triple flanges, etc.).