i don't know about the ecis, but everyone sees to be very happy with theirs. i almost bought that myself, but the dinan dealer convice me otherwise. he keeps suggesting that the ecis in not really a cold air intake and that it would be sucking in hot air so it might cost me a few hps. i dont want the risk so i went ahead and got the dinan one. but from what i heard from other people that has the ecis, they work just as well and cost half the price. of course if you like the carbon fibor look, go with dinan. i have mine for about a month now, and i love it, i also got their throttle body, stage 3 chip and strut bar. i was going to get their exhaust too, but i turns out it doesn't fit my car (98' 323is). i bitch them out a little and they agree to mail me a dinan badge even though i don't have the required 10 points so i'm happy.