Need help with ecu<<

[teamMeadows240]

I've got a 1990 nissan 240sx with the Ka24e. we rebuilt the motor, lightened rodsforged pistons- board 40 overjim wolf cam550cc injectorswalbro fuel pumpnew valvues/ sealsjust about everything, but the only problems is, i've never had to deal with the ecu before. some people are telling me to get it sent off and chiped and others say you have to buy a whole new piggy back.either way i havent got the slightest clue as to where to send it to or where to buy an ecu for a single over head.if anyone has any suggestions or knows what would be the best to do please help me(i hold a personal grudge agunst ebay i would never buy an ecu from there)i only have $650 to use