[Aussie Mike]

I believe the smog check in the US means plugging in to the OBD2 port and seeing if there are any emissions related trouble codes.

Probably wouldn't have passed the tail pipe sniffer with that cam in it.

Here's some usefull ECU identification info:

1999-2002 PCM
Running a 32bit Motorola Microprocessor
Flash capacity is 4Mbit (512K).
PCM HDW numbers are either 16220610 (1999-2000) or 09386530 (2001+).

2003-2004 PCM
Updated Microprocessor but is still very similar to the 1999-2002 PCM.
Flash capacity is 8Mbit (1Mb).
From the outside it looks the same as the 1999-2002 PCM except instead of a Red connector it is Green.
PCM HDW numbers could be one of the following -
12570558, 12580786, 12583659, 12583660, 12589161 or 12589162.
Note: Some of these PCM's are not interchangable between vehicle applications.

2005 LS2 ECM
LS2 ECM is known as the E40.
Has an upgraded CPU and is a completely different animal to the previous units with different connectors. This ECU also no longer does the transmission control.

Cheers