Got a 99 accord f23a1 turbo build my tuner said to get a p28 ecu an hondata s300 but isn't p28 a civic ecu

 

It doesn't matter if it came from a civic. The key thing is to get it professionally tuned for your specific setup. You will also need a conversion harness.

You may want to start doing lots more research before attempting a turbo build.

 

Go with what your tuner said. After all, he is the one tuning your car.

Also, your Accord ECU cannot be tuned.