Wow, what a super straight, non rusted, or beat up cool coupe to start with! You could find an older LS Escalade to rob the engine and trans from. If you are on a budget, I'd try to stay pre 07 ish. You can find 6.0/4L80E combos for around $2k in my area. An LS swap can be done on the cheap but you have to be careful because it will get expensive in a hurry. There are low sump ching chong oil pans available now that are affordable. Like Mike said, accessory drive kits can get expensive in a hurry. The truck stuff should fit that car if you put the engine back near the fire wall. I'd at least try to make them work because getting parts later on will be easier IMO. Plenty of places offer modified or new conversion harnesses and there are a lot of places to get the ecm flashed and or tuned as well.