you'd need 99-00 Si axles, and you'd be good to go. might have to wire up VTizzle depending on what car you are putting it in. that would come w/ a GSR tranny FYI... then, you would need to buy whatever broke when i came with the motor. anytime you ge ta new motor, it is always a good idea to do timing belt/waterpump ect. when you buy a motor you know nothing about. i dont know anything about that company but H Motors is awesome. There is also some company that sponsors this website, so it's gotta be legit. just be careful when you buy a motor off the intraweb. because the motor is JDM the wiring will be a little off, but if you can use the stock wiring in your car, swaps are actually fairly easy.
edit: just saw your car is an Ex: Make sure you get an OBD2 motor(Like the one you linked too), then everything will be plug and play. So yeah good luck, and if you have any Q's about your swaps ect, post 'em up.