Here is your best choice(s).
http://www.sdparts.com/product/MMS11...rnKeyWECM.aspx
If this is too much, try these:
http://www.sdparts.com/catalogsdparts.aspx
Turn key and ready to go LS3 engines.
These are the best I have found and they are not even Supercharged yet.
What do you think?
Ty