Jody pretty much covered the basics of the event (thank you). The only thing I would add for someone who hasn't done this type of event before would be that the Speed/Stop Challenge could be equated to an approximate 1/8th-mile drag race into a 40-foot box. Basically, get your car into the box and stopped as quickly as you can without going over.
In terms of appearance for the OUSCI & SEMA, what we're really trying to avoid are cars that are not quite finished yet- unpainted hoods, primer around wheel wells, etc... If the selection committee likes your vehicle, they'll invite you to the OUSCI. The requirement about being at SEMA lets everyone know that the commitment doesn't just involve showing up for the OUSCI, but having the car on display all week at SEMA.
The owner doesn't have to be there all week, but the driving force behind this event is promoting the industry, from the owners and builders to the companies behind them. Having all the participating vehicles at SEMA helps add visibility to the event and increases the exposure for everyone involved. As Jody mentioned, some OUSCI vehicles will be invited by companies to display their vehicle in a SEMA booth, like Mary Pozzi's Camaro at the Hotchkis booth, etc...
Optima secures both indoor booth space in the main hall and a car corral outside and between those two locations, we'll have plenty of space to showcase all the OUSCI vehicles. If you have any other questions, please don't hesitate to ask.
Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
www.twitter.com/optimabatteries