Possible the association to 05 SEMA added provenance appealed to a collector.
"The actual SEMA Design Award winning 2006 Pontiac Solstice. 2005 SEMA Design Award for Best GM Roadster. Customized by RK Sport out of Murietta, CA. It has been featured in no less than four magazines and is one of the most photographed SEMA roadsters ever. Completely customized inside and out, this is truly a unique and collectible piece of automobile, SEMA and GM history."
Wheels look to be rare too:
19" TSW rims (3) and 4 Vderstein Sessanta tires