At the moment, the only choice of cables that won't loosen the ports are the OEM triplefi 10 cable, old FLC8 stock cable, stock FLC8s, and the FLC8s silver cable made by forrest. Although forrest did say these use the triplefi.10 connectors, he uses steel pins which likely has tighter tolerances than all the custom stuff you see floating around lunashops or ebay, which are mostly brass. The 0.01mm difference in pin size is enough to loosen the connection ports so that the stock cables won't fit as snugly anymore. There was a user with a cheaper triplefi 10 custom cable that had a pin breaking inside the port when he tried to remove it, requiring him to send the iems back to forest to get them fixed. Unless you're completely sure what custom cable you want and do not intend to routinely change cables, I'd say you could get away with any of the triple.fi custom cables available now.
Personally this was actually the dealbreaker that is making me hold off on purchasing these but as you can see from this thread, there are not a lot of users that have issues with the current 3 cables available and the IEMs themselves have stellar sound quality
I PMed forrest regarding connectors and he did say the future models would be using the standard 0.78mm pin connectors so I will be definitely waiting for those!