Yes, a 1989 Civic Si engine can fit in a 1990 Civic LX with some modifications. Both vehicles share similar chassis and engine bay dimensions, making the swap feasible. However, you'll need to consider compatibility of engine mounts, wiring harnesses, and potential modifications to the exhaust and intake systems. Overall, while it's a doable project, be prepared for some additional work to ensure everything functions correctly.
No it will not.
yes it will
Only if the civic is a hatch, sedans have longer hoods. civic hatch and crx hoods are interchangable.
YES
No. The Civic seat rails are different.
yes if it has the same body style it should, but the v-tec engine is different than a stock one
no
Yes it will. Make sure you replace your motor mounts as they are most likely torn.
yes
With some modifications, yes it will fit
No
yes