The first X2 (version 2 essentially) was the M140X2. The new M200 and M300 are actually X3. Then the R650X2 with 40+1 tools came out about a year or so ago. This machine was a radical change from the R650X1. The S300, 500 and 700 machines are now out as X2. It's been a couple of months. The S300X2, S500X2 and S700X2 machines are the first major revision of those in about 6 years. Casting updates with improved dynamics, provision for Brother robot on casting for 500 and 300, sheet metal improvements, coolant/chip flow improvements, Tool changer improvements, larger control cabinet for automation capabilities, FASTER.... Just installed two S500X2 machines in a shop with X1s and cycle time dropped about 10%. That was with faster T200 rotaries but machine itself is noticeably smoother and quicker. Hard to imagine because the X1s were very good already. Too many details to get into here.