E30's 1980 ? do you mean e21 1979 > 1983 , twin exhaust would make it a 323i six cylinder 143hp , if it had twin exhausts it would have been this model , if not a 318i model , if twin headlight a 320i model . Most people do not go near "working these cars " the most common swap is a 2.7eta bottom end on the 2.3 head . the problem is with the mechanical fuel injection this is very hard to tune to get anymore power . If he was really smart he would have done the 3.0-3.3-3.5 633-635-733-735 engine swap and power would have been around 218-220hp with 300ish nm .
the guy had had a single exaust but welded another pipe before the rear muffler so it looked like a twin system i laughed when i saw it