Speedconcepts - Home Speedconcepts, Porsche, Fatty, 55 Chevy, GT-R, SLS, Mercedes SLS, Nissan GT-R, GTR, Nissan GTR, One Lap of America, custom fabrication, race car, race shop, racing, street performance Welcome to Speedconcepts. We are a custom automotive fabrication, street performance and race shop. If you can dream it, we can build it.