I have 2 1988 civics one is going to be used for auto cross i plan to drop in a B19C1 in it and coil overs racing seats (required) what else should i do to it

weight reduction, and bars... (I.e. Strut tower, swat bars, c pillar.. etc..) And a roll cage couldnt hurt.

get a rule book step one

put down your wrenches stop do not pass go.
If you are really going to auto X find what class you want to run in get the rule book then plan then you can pick up a wrench.

unless you are expierienced at this which i doubt because you are asking i would run the stock class. i think the rules say that you can use any part that came on a different trim level of the same year and model of your car. so go grab a racing harness and helmet and go steal everything from a si. you can be in any class but if you want a chance at winning dont go into a modified class