Yes, the original crossover pipe was tiny. The only company to make an X-pipe for the Lightning is Bassani... quality work. They also make equal lengths, high-flow cat pipes, and both front and rear exit cat=backs.
There are a few other companies that make headers, FRP, JBA, and Hooker. No long tubes specifically for the L, but some are making the mustang 351 conversion fit, by either notching the frame/motormount or heating the pipes and bending them out.
Oh, Cooks makes long tubes, but they are only sold through JDM.