I'm about to start piecing together my 2jz-vvti build but one of the hardest decision I've come across is what computer I should use to piggy back off of my stock ecu. From my research I've heard some bad and good about piggy backing, some horror story's of the stock ecu try to re-compensate and eventually ruining the motor.
Someone please help me make this decision

 

There is only one choice. And that is to buy what the experienced 2J tuner that is going to be tuning your actual car tells you to buy. Yes there a caveats to different brands/models but most will work fine if the the tuner knows wtf he is doing.

 

Thank you for the reply, that makes sense to get a set up the tuner is most comfortable with and recommends, problem is the guy I'm most likely going to go to is. Do you know of any serious downsides? My gs300 is my daily but I do have a back up vehicle. I want to keep the build for now just light boost so she has a little more *****, until I get something to replace her. Then I'll try and poor money into my spare motor.
btw if you have any info/resources for gs300 building plz shoot it my way

 

I have seen some decent tune and number on MAP ECU. If a piggy back is what youre looking for, might want to look into that.