My friend has a 1990 CRX Si and was wanting to do an easy cheap swap. My question is which of these two motors would be able to get more peformance with bolt ons no forced induction. Either the D15B SOHC VTEC motor or the dohc ZC motor <---green 91. From what ive read both will bolt up to the stock si tranny, and use the same motor mounts. But will you have to mess with his fuel injection or anything like that. Any feedback would be great. Thanx.