i actualy just got a siRa1 for my 91 CRX dx. i havnt thrown it in yet cuz im rebuildin it. but it has 160hp, and the siRaII has 170hp. and is obd 1 like Marine said. but if ur rebuildin it they the 10 extra hp wont realy matter at all. but if ur throwin it in stock. then id go wit the siRaII if u have the $ then thow easy stuff into it like cams and bolt ons. but ull need to convert the obd 0 - obd1, if it is the HF model i think you need to do somethin with the hubs, because they are not big enough or sumthing. but you would not have to convert the injectors like i do. DX is the only crx that u g2 do that to. but good luck bro.
Tyler