I just had the same experience. Lost a channel on my E4Cs, and did the RMA with Shure Canada. Just got the SCL4 in exchange, and they look almost identical, finish is slightly different, a combination of two textures, glossy and matte.
Right out of the box they are similar, excellent reproduction with acoustic strings, great imaging. One thing that's missing is the high-end rollof. I used to use the iPod treble boost, especially when the E4Cs were breaking in, but it is not necessary with this pair.
Either there has been some slight modification, or my my high freq sensitivity has improved.