Ever wonder what happens to show cars when they're done being showed off? In the case of General Motors, they end up in the GM Heritage Collection. But things can get crowded in there, what with all of the automaker's many brands creating so many show cars each year. So sometimes they have to sell some off. And that's just what we have here.

Coming up for auction at Barrett-Jackson in Scottsdale in a couple of weeks are not one, but two show cars built by Cadillac and displayed at the SEMA show over a decade ago. And GM's loss could be your gain.

First up is a 2008 Cadillac CTS Sport sedan displayed at SEMA in 2007, ostensibly to preview the new CTS-V that followed the next year. It's based on the second-generation CTS, but received a new front end, hood, rear spoiler, and black 20-inch alloys hiding yellow brake calipers. The engine remains the stock 3.6-liter V6, rated at 304 horsepower and mated to a six-speed manual. It's been driven, showing 22,455 actual miles, but it's being sold on a "scrap" title issued by the Michigan Motor Vehicle Department in 2009. More tempting, though, is the 2007 Cadillac Escalade that's being auctioned off separately but alongside it.

This big sport-ute was also displayed at SEMA, but packed a far bigger punch – namely in the form of the 6.2-liter supercharged LSA V8 that would later power the CTS-V to the tune of 556 hp and 551 lb-ft of torque. It was (and remains) the closest Cadillac has come to producing an Escalade V, and also featured Brembo brakes, Enoch springs, 24-inch alloys, a billet aluminum grille, Recaro bucket seats, and a smattering of unique body panels. Sadly this one is being sold on a bill of sale, and can't be driven on public roads any more legally than the aforementioned CTS Sport – but a more powerful Escalade you're not likely to find, especially built by GM itself.