Of the 5 vaiables (hot/cold impellor H/C housings, bearing housing) only the bearing housing is the same.... But by looking at the RS2 and the stock k26 you can't tell a difference, except the cold intake impellor is obviously larger, the changes are subtle, but in turbos subtle changes make BIG gains..... When the details of the RS2 upgrades come available you'll see what I mean.... Scott