The hydraulics in the car will be degraded if not shot (clutch, brakes).
I like the F20Bs, but most of them are the 58mm TB/180 hp automatic version. The ECU you will get needs to match transmission, and if it's auto you WILL need the F20B transmission as it has 3 wire main and counter shaft speed sensors. I can walk you through wiring them in place of the two wire sensors, and the one or two pinout changes that go with it. If that Prelude is auto it will have the mode selector switch and manumatic shifter that the Accord/Torneo's with the F20B got... pretty cool to be in an auto wringing 8K, not fast in those chassis but it makes a nice commuter.
Never stuck one of those swaps in a Prelude chassis, but the H22 PS bracket is needed with (?F23?) crank pulley to make the PS setup work as the F20B doesn't have a 2nd belt pulley for the PS. Frankly, the H22 pulley should work but IDK never done it.