I'd investigate the 2008-2012 Colorados that had the LH8 & LH9 engines to see what may be common, or pretty close. I bet you'll find those parts off a Colorado quicker. The oil pan I *believe* is available as a GM Performance part. I don't have a part number handy. Maybe someone can chime in. If you keep the I-5 4L60e, there's something different from the Alpha 4L60e. Pilot bearing, or something, I can't remember the details. Another thing to investigate. I'm guessing you'll do a 6L80e anyway.