ProFurl is another good choice
The Harken, Furlex, ProFurl and Schaffer furlers should be about the same price for correct furler for the C-30. All four are excellent units and will last a long time. I had a Hood SeaFurl on my '87 C-30T and hated it (continuous line, couldn't reef, could only furl, etc.). I had a Harken on my first boat (a Cal 27), a Hood on my C-30, and my C-320 came equipped with a Schaffer 2100. The Harken and the Schaffer were quite reliable units.The CDI uses a plastic extrusion, replaces your halyards with its own internal ones, and has NO ball berrings. Although some people have them on C-30s, I wouldn't recommend this unit for anything bigger than a C-25.Friends have had the Furlex and the ProFurl on their boats and liked them very well. I've never heard of Spin Tech.Don't compare apples with oranges. The ProFurl, Schaffer, Harken, and Furlex are roller reefing units while the CDI is a roller furler. The difference between these is that the former can be used to decrease the size of the heasail reliably when the wind pipes up while the CDI can only be used to completely roll furl the sail. The CDI is much less expensive as a result. Ya Gets What Ya Pays For.SteveAlchemist C-30T #4764Alchemist C-320 #909