“We need your help,” Tesla wrote in a Feb. 19 e-mail to its customers in Indiana. The state legislature was about to move forward with a bill that would have forced the electric-car maker to find a franchisee to operate its one showroom in the state, setting a precedent that would make it harder for Tesla to open others elsewhere. The company claimed the legislation reflected the interests and influence of one rival: General Motors. “Don’t let GM tell you that your only option is to buy a car from a traditional franchised dealer by shutting out Tesla,” the e-mail continued. Tesla asked recipients to contact their lawmakers.