where can i get a b20 with transmission, ecu and block with less than 50k on it?

also which is the best agine to put into a civic 92?

 

Why do you need the B20 tranny and ecu? If you're planning on putting the motor into your civic you can't use anything but the longblock. Even the intake manifold won't fit.
But...if you really do need one... check out: http://www.importautosalvage.com http://www.copartfinder.com http://www.thepartstrader.com