I may be wrong but, AFAIK, the K318 tops the new range of "improved" buds with the K313 coming in second and qualifying as "high performance" whilst the lower ones are only "performance" buds. Possibly the new K313 is quite close to the old K319 in performance and quite cheaper as well. K318 is also much cheaper.
I may try them at some point. Not just yet though as I should have an M2C coming(from the loaner thread) and Jack from Hisound has sent me a pair of LIVE buds. When I find a deal on them I'll pick a pair of the K318. My current PMX680 and KPH13(half of the KDE250) are already better than the PK2 as were the loaner pairs of M2C.
As I said, I've never heard the K319 but it doesn't seem to be that great in the current market(the last post is over 2 years old) and I do not feel it a stretch to think you are hearing right that the 313 are similar. A new range comes in and should be better and cheaper.
Edited by jant71 - 1/15/12 at 1:59pm