Right on GMPPs website is the "Dovetail Rear Spoiler" from Dale Jr's car:
PN 92207433 MSRP $400
Click here:
http://www.gmperformanceparts.com/2008sema/
Then click on his car. A flash window will open up seperately and you can click on any of the SEMA cars and the parts that are available come up w/ PNs & MSRPs.