I have a JDM B16a swap done to my '90 CRX and the ecu that came with it was a pr4. I know that the pr4 normally doesn't control vtec because it's from a ls integra but the guy who did my swap got it to work but to me it seems like it kicks in sometimes and then sometimes it doesn't. I want to switch to either pr3 or pw0 but need help deciding which is better and if I should go chipped or not. I'm running OBD0 and want to stay that way for now. Thanks in advance!!