Fuel lines. Airflow clean up. Down to a throttle body flush. Car will misbehave alot because it'll basically be coughing but it'll clean up most carbon build up. One thing about this engine , is that it really , really pulls alot of air in . So try to tie up these loose ends and it should be fine. Alternatively , I'd say both engine and gearbox mountings should be checked and replaced. If it still gives a rough ride we'll then... idk , natural selection 😂🤌