E30 Zone

Worth replacing standard air box and what for?

No

Not worth it unless you got a turbo and need increased airflow. Buy a decent panel filter instead!

Buy a standard panel filter!

Have your injectors refurbed (injectortune on here), Chip it (speedtouch on here), then stroke it, and leave the air box & filter alone in all instances.

You could add the induction kit with a 12v fan blowing air into it. Adds up to 25hp. Add second fan in antiphase on the exhaust sucking exhaust gasses out, add up to anothet 25hp. Thus all in upto 50hp plus up to several hp from the induction kit.

Otherwise you can assume BMW engineers knew a thing or two about engines and designed the standard airbox and filter that was able to supply all the cool air the engine requires and leave it be.

Id go with a decent panel filter , K&n or piperx
Ran mine with panel and cone
At night with a cone and one headlight out and the cold air getting in it seemed to rev better and smoother , But in town in traffic it suffered with heat soak and was naff
Seems quicker as its more throaty / noisier with a cone
But its not all about noise

Steve-E30 wrote:Id go with a decent panel filter ,

Which would be a genuine BMW one or OE equivalent.