I guess I was lucky that Z1R was my first deep dive into IEMs. It was love at first listen when I demo'ed it, and the crazy deal SonyAU had going during a one-off sale at the time, I couldn't resist.You have to go through the IEM journey or you really don't know what is your best.
Nearly 12 months later, I can't think of how I could 'upgrade' from it. Only thing I'm thinking might be EVO or EXT? Not sure if our how I could demo the latter, and when I did get a chance to hear the former it was amazing, but I couldn't see spending nearly $2k more than I had on the Z1R for it.
For now at least, that 2k would be much better spent on the 64Audio custom I'm after, which will complement the Z1R nicely in my collection.