UPDATE: here is the page that has the cam sprocket info for a 99 notice the two different part numbers for camshaft no. 2.
The camshaft sprocket for camshaft no. 2 on a 2000 RS 2.5L (EJ251) which the engine is installed in there now is 13019AA041.
Now in the link I posted
http://www.subaruparts.com/diag/?model=5&year=1999&style=RS&body=sedan&scn=0&category=013-1
It has two different numbers for the 2.2 L. I am calling subaruparts.com to get further clarification between the two cam sprockets for 1999 2.2L tomorrow. ***I'm assuming if the engine didn't start it is part number 13019AA041 for camshaft no. 2 which came with the 2000 2.5L and in actuality it needed a 13019AA051 camshaft sprocket for camshaft no. 2***
Could it hold true that a different camshaft sprocket could cause the engine not to run at all correct being that the ECU could expect different sync signals?