wire harness for the pcm, the tcm/trannys are the same (as far as info you are looking for) you will also need a pcm, and some bin file editing MAY be needed due to the yr differences & the car (not sure how your BCM will like talking to an 04ss PCM) Theres a few places around that will do all the labor for~800-1000 including the computer work (depending on where you live & your tech bkgrnd, you may want to look into this) The earlier Imps have a Steel cradle (IIRC it changed either in 02 or 03, but you should be able to tell which one you have fairly easy, black=steel, silver=alum, and the newer ones have an alum. but the cradle should still work as its the same as on the GP's which also came w/ the L67. There's a weight savings of 15-26#s IIRC. The EASIEST way ( if you have access) would to be unbolt the steering rack/struts/wires/hoses and drop the cradle to swap. I am not sure if the 3400 engine mounts will work or not, but you can buy aftermarket lower engine mounts from a few of the 3800 performance sites if they dont. It's not an easy swap by any means (just a heads up) but $900 for engine + trans is a hard offer to pass up (I've seen complete L67s go for that alone)
hope this helps a little, if you decide to go thru with i t, i can start digging up more info for you.
Also since the engine is out, you might want to look into mods (specifically a cam/timing chain), it'll be the easiest time to do it
