As long as you are positive that you have no emissions restrictions you can rip it all off. This is a very popular topic here on YJ - JF. But if you ever move or sell it in another state you may find that you can't get it registered an almost everything has to be put back on.
Do a search for "Emissions YJ? you will find dozens of threads.
As far as computer controlled... yes you have it on a 1990 but you can all but eliminate it by doing the "Nutter bypass" If you have a stock Carter Carb there are a few extra steps related to modding the carb, any other aftermarket Carb and the Nutter is a must do.
The biggest pitfall to removing all the stuff is vacuum leaks. Pay close attention to the details.
One does not establish a dictatorship in order to safeguard a revolution; one makes a revolution in order to establish a dictatorship. - Orwell