Luke Schneider wants to avoid the “PT Cruiser Lottery” of rental car users hoping to get the least bad of the leftover cars. Schneider is the CEO of upstart rental agency Silvercar, where every car is a silver Audi A4. The start-up got cash from angel investors CrunchFund, SV Angel and others. “We want to do for rental cars what iTunes did for music,” he said. Schneider, who came to Silvercar from Zipcar, where he was the CTO, says it's not just about guaranteeing an entry-level luxury sedan. It’s about choosing cars packed with the technology to make Silvercar’s model work.