TIE Interceptor.
In building the Interceptor I used elements from the TIE Fighter and Advanced TIE to show the relation. But if the Interceptor is based on the standard TIE, how to explain the Interceptor matching the A-Wing in speed and manuverability? You take the safeties off of the reactor and engines.
The TIE reactor and engines are capable of producing insane amounts of power but are limited (de-rated) to prevent failure. The Interceptor's reactor and engines have the limiters turned off. They now operate at or near design limits to provide the power for the additional weapons and engine output needed to match the A-Wing. The trade off would be a corrisponding reduction in range and endurance compared to the standard TIE.