I have the AFE installed in my 4.4, other than the big azz cold air filter looking super cool when u open the hood I can't really feel any improvement in performance, maybe it sounds a little better than the stock filter but I don't think the difference is much.
I agree that in order for u to gain the most performance then you will have to do an exhaust upgrade too.

thanks for feedback, ive only had the x5 for 2 weeks, did exhaust last week, found it hard in perth to find someone to modify as not many people change on the x5 here,(sleepy perth), put two lukey mufflers on,(local brand) and increased pipe to 2 1/4 inch back from the cat, even installers were impressed at start up! mild steel as well, got talked out of stainless, only cost 550 ausssie, happy with results, loud but not overboard.... as for afe, i read a few forums, people say it deffinetly improves performance, but i am concerned about effects with computer as obviously it will be taking much more air, very hard here in aus to get information. will consider chip, but it is $1,700 aus, only increases x5 by 10 kw, mmmmmmmmmm, fair bit ...........

The computer will make the necessary adjustments within a few minutes after installing the AFE.

thanks zero, im waiting for afe to come from america, have only changed my exhaust from the cat back, is yours the same or complete new system?
do i need to remap for intake?

zero, luv those mods!!!!!!!!! that is one sweet bmw!!!!

what is the pioneer sub? and that is one strange looking box? would like dimension if possible so i can do same, have you changed any other speakers? also how do you go about installing that amp?

does someone have a link to the AFE cold air intake?

My friend had told me to replace my air filter with something like this,
http://www.knfilters.com/search/prod...x?Prod=33-2255, is this a purely psychological improvement or is it worth doing?

Thanks for the compliments! Mine is a cat back system. Its a good idea to remap the system after the install.
Article from the main webpage that will help you install a sub amp of any brand: http://www.xoutpost.com/articles/x5/s...ctory-amp.html

Yes, I did swap out the crappy OEM speakers for MB Quarts - much improved!

Thread regarding my sub enclosure (but no dimensions yet!): http://www.xoutpost.com/x5-e53-forum/...installed.html

Thanks StanF18! The remap via GT1 was done by a long time BMW guru mechanic friend of mine - no after market company was involved. No tranny software also.

Not worth it considering the AFE is over $300usd but it sure does add some mean sounds (you can hear a high quality sound clip of the AFE in my sig below. AFE is panned to the right channel)

AFE link: http://www.afefilters.com/

Some people run the K&N, maybe they can chime in...

I installed the afe intake on my 01 4.4. no big difference at all

:iagree: As is sometimes mentioned, do you think BMW knows less about their engine and airflow than some aftermarket shop? Plus the oil on aftermarket wet filters are known to mess up the mass airflow sensor.

It helps a little, but only at higher speeds. Not worth the extra $$$. I've been wanting to put the oem back on. But been to lazy. I want to see the difference. Once I do that I'll let everyone know. I think the reaction time will be different compared to the AFE. Reaction to the WOT. I think there will be some sort of split second delay upon WOT. But then I could be wrong. I'll see when I put the OEM back on.