Thomas,
Good question. There is already a jackshaft installed on your car from the factory, but you can buy a fully machined aluminum version from Super Coupe Innovations that is lighter in weight, and therefore frees up crank HP. If you want a good modifcation that is easy to install, and has good cost vs performance gains, I would recommend you look into buying one.
There is a group purchase taking place on these within the GP forum. I think you can buy them for $140 now, or somewhere in that price range.
Good luck.