96' 4.0 into a 91'? Sensors, connectors...

So I'm picking up a 4.0 from a 96 Xj and going to install it into my 91 XJ. Is the pulley/accessories the same? If not which should I keep? What about the electrical connectors? What other issues will I face?

One more thing, is there anything I should do to the engine bay or engine itself while it's out?

Also what about smog here in NorCal? O2 sensor? Etc?

What about the exhaust? I would want to reuse my Borla from the 91.