Originally Posted by robitrice
and why should he not use the STI engine!? I would suggest buying a new short block if you can afford the down time. Get your heads rebuilt and put on the short block and call it a day. If you need a quick turnaround find a used motor from a reputable place and swap that in and start saving for either a rebuild on the blown or for a new shortblock.
An STI ENGINE will have different heads (depending on the year) thus Dual AVCS, which will require engine harness and computer. STI SHORT BLOCK is virtually the same as EJ255. In addition, questions regarding swapping to manual transmission, in the same thread, indicates to me that tho OP might not know the differences between engines. The Quickest way out is to swap out engines and have a spare to tear down and build.