It's the "chassis code" that you hear the ricers spoutin' off about all the time. It's not exactly a chassis code though... the DC2 GS-R is the same chasis as the DC4 LS, but the DC2 Type-R is a different chassis from the DC2 GS-R. Of course, there aren't really any huge differences between the R and non-R; it's mostly just braces to stiffen things up.