Cheep fix..... Battery cutoff switch. I know its not the answer but at least you could save yourself the hastle on a $500 car.

That being said, there is a plethora of things that could affect the battery. Ive seen a bad light switch on a glove-box allow the light to stay on over night totally drain a battery. Might be something stupid. The fact that it was blowing fuses prior to the ECU replacement sounds more like some kinda short/over-voltage. Just some things to think about.

If it were me. Batt cut off switch. Say goodbye to your preprogrammed radio stations. But who listens to the radio anymore anyway :hsdunno: