Any dyno-proven intake mods? 540i m62 E39 - Bimmerfest - BMW Forums

It helps (cai) on some cars as a stand-alone but here, unless you're prepared to go down an expensive rabbit hole, just do the exhaust, engine/transmission flash and save up for a supercharger or headers, performance cats, free-flow exhaust and a good muffler. Then, save the last mod to be the CAI and you'll definitely feel a increase of 12hp.

This was my old 540i e39
And I thought about doing the same thing to my wagon: adding the bigger plennum and everything. I've gone over hundreds of posts about cai's on e39 and e53's and find no evidence that it does anything on its own but look and sound cool. UNLESS you do other stuff too, then it all works to give you more hp. A software flash to your engine computer and trans will do more for you as stand-alone mods than anything on the intake side. Headers next, but an s/c is the only thing that'll make your eyes water with joy after the install.

I'm just trying to save you some money on superfluous stuf. if however you have a pile of it and will never go s/c and stay naturally aspirated, go dinian intake, maf, t/b, manifolds, coil upgrades, software flashes, headers, cats, exhaust and muffler.

You can always go s/c later and be glad you built a foundation for it to breathe.