Hi Tim,
you can find some pictures of the Dinan CAI at the following URL
http://www.janixworld.com/x5/dinan/airfilter/ .
The design itself is not very complicated but there have been
a number of reports of folks who installed aftermarket CAIs
and failing MAFs (due to oiling and other issues). The Dinan
CAI is not sold as a standalone unit but requires the
engine SW and modified MAF as well.
I think the answer to your question regarding whether the
upgrade is worth the money really depends on each individuals
preference and priorities. Having gone through the full S2 package
on my 4.6is I can tell you the CAI will certainly add a nice sound
from the input side (as does the Dinan/Eisenmann etc exhaust for the
output). However you will not get the "Wow" effect in regards to
horsepower (after all the X5 has the areodynamics of a brick), one
can argue the S3 package (Supercharger) will give you the real
kick but it's also a very different animal (price wise and in terms
of modifications).
In my experience I'd say the key to any Dinan modifications is whether
you have a good relationship with a Dinan/BMW dealer and how they
will take care of you in the longterm. This is a very sore point for me
as in my case I experienced problems and neither Dinan or BMW turned
out to be very helpfull (both kept telling me I have to work with the
other side , or they can't find anything "wrong"). The Dinan warranty reads
nice on paper but you need to realize that any warranty claims in regards
to transmission and / or engine will have to be covered by Dinan as BMW
will not even look/diagnose the car (a Dinan/BMW dealer will/may).
Even if you have a great local dealer (like I have) their hands will be tied as
the car will be flagged in the BMW system as a Dinan car and the dealer
will not get any response from BMW NA tech departments such as the
transmission hotline....
There's also the issue of CPO which is yet another story for Dinan cars ....
The transmission software has made a difference in shiftpoints and will
make it more fun to drive in manual mode.
I don't want to put you off but just provide my opinion having lived
through Dinan issues and some very frustrating BMW/Dinan dealer
experiences in the Boston area.
- Jan