There are no guarantee's but there are things that can be done to improve your chances. Apparently once the new cab goes live then all new orders will be provisioned on that. But if I used my existing line, cancelled FTTC and then re-ordered on my existing line, there's a very good chance it would still be connected to the ECI cab. Ordering an ADSL service in the interim would solve this problem, or as I intend to do simply order a new line. There is one guy on Kitz who's line should be connected tomorrow, and we'll get to see if he's managed to get onto a Huawei cab.
There's quite a bit of info in this thread on Kitz
If the G.INP fix works, and and the new SNR margins work just as well on ECI then I may not change, I'll see how things go.