You can't buy a real Guiliari any more but the repro's that one of the members here sells on EBay look good. My seat is a genuine Guiliari, but after 30 years the foam has started to deteriorate, and I might need to get it replaced.
I do agree with Grumpy though, I do like the sitting position and I wouldn't swap it for an OEM seat. Like Grumpy, I haven't had any experience with Corbin seats, but I've heard that they're more into "form over function" than some other seat manufacturers. Cheers, Terry.