A program that never became a standerd carft, the TIE/ad series is no less impressive for it's low numbers. Intended to replace the TIE/ln in many roles, it was the first group of TIEs to carry shields and a hyperdrive. Using a long set of solar panels, that would later be used on the TIE Bomber, it is not as manuverable as teh /ln. Many pilots feelt hat the higher speed more than counteracts the loss of nimbleness, as a good pilot can make up for poor performance, but only the Emperor can help you eek out more speed from a slow engine. They use advanced targeting systems and stronger laser cannons, but the boosted powerchambers experince greater erosion than the standerd models, thus requiring higher level of maintence. This seems to be the running theme of the TIE/ad series, as all of the systems require a higher degree of caretaking for reliable function.
After the TIE Advanced x1, there would be three notable variations. The first was a custom made craft, given as a gift to Lord Vader by the President of Santhe/Seinar, which he used in the Battle of Yavin. It is believed that he used this craft until it was destroyed during the Battle of Endor, resting in it's luanch cradle on the Executor.
It was followed by a the TIE Advanced x2, which featured slightly improved systems, a more powerful navagational computer and a set of field landing skids. There were fewer of the TIE/ad2's made, but they were a more popular craft with pilots, who no longer needed to return to specially equiped ships or garrisions to land.
Finally, there was a production run of the TIE Bomber Advanced, which removed one of the two bomb bays for the shields and hyperdrive, and included the landing skids.
There is a TIE Advanced x3, but this considered to be the protype of the TIE Interceptor, as it used the body of the Interceptor, but it mounted the TIE/ln's weapons in a chin mount.