ITB's change up the powerband but they don't alter the powerband too significantly.

Without ITBs I would say that motor would run you $7-10k depending on who builds it and how long they spend doing it, add another 2 grand for the ITBs.

Please tell me you are not seriously considering putting that sort of thing in your 1988 Accord DX. Because aside from the fact that the entire concept is completely ludicrous, you will have to rewire the entire car to run fuel injection or convert the motor to run carbs. Side-draft Webers are not cheap.