about the best you can do with that motor to get some extra grunt,
is perhaps on the exhaust a x-pipe, a uni-q piggyback perhaps.
other than that, have a look on e30clubsa.co.za there are well known recipes for doing a stroker build whereby the motor essentially becomes a 2.8
as far as i remember this is good for around 140-150kw and 250nm ore thereabouts. stock she is 125kw and 220nm
as for the stock ecu, theres not much "wrong" with it, perhaps you need to do a reset on your car, disconnect the battery for 20minutes, now start the car let it get warm then take it and wring its neck.
it will now "learn" a more agressive map and she will feel nippier.
having had a e30 325i 89 myself for 3yrs i can also tell u these cars
eat sparkplugs, in that replacing the sparkplugs seems to yield a noticeble difference.
also make sure your tappets are always set.
