i blew a home in my sohc Ex engine, and i figured that since i still need a new engine, i might as well get a dohc engine. i heard i need a new trans if i get a dohc. and a ecu, w/ axles, right?

i have an automatic ex, what is the best engine for it. i heard an si engine wont work since the si's come with a manual trans. anyone know were i can get a cheap but goo engine w/ trans?
-Thanks