[h=2]First generation (1992–2000; GC, GF, GM)[/h]
[h=2]Second generation (2000–2007; GD, GG)[/h]
[h=2]Third generation (2007–2011; GE, GH, GR, GV)[/h]
[h=2]Fourth generation (2011–present; GP, GJ)[/h]
As of right now, I have no idea what the WRX and STi chassis codes are for the 15+. I have heard VA for the 15 STi, but there's no information at all yet. You'd have to check on the VIN!