The solstice/sky 5 speed is an aisin (same company that manufactures the R154) 5 speed transmission found in several cars and is considered an updated r154. There are many things that interchange (such as bellhousings), however there are some other technical challenges.

http://www.supramania.com/forums/sho...stice-Solution

Start reading. But it is a verified fact that the AR5 transmission is an update to the r154.