considering your 4th gen is a dx, which is a 2 injector car, it would have to be converted to multipoint injection, and also the jdm d15b should be the vtec model, it would take a bit of extra money to get it in there and running exactly the way it should. about the $900, if that is just labor, its about right for a company to do, but if that includes the obd0-obd1 conversion, multipoint wiring and new ecu you will need, it isnt too bad of a price. if you just want to replace the dx engine in ur car, i wouldnt try finding a jdm engine, just find a 88-91 engine and put it in ur car and leave it w/ the 2 injector setup, would only cost about $500 total w/ engine and install. i may be able to help you out some, if interested PM me.