Im gonna go ahead and get a Alta cai..loudest.lightweight..and the other big box ones seem heavy!! also read that it does in fact seal against the hood!
I have a question....Im trying to figure out where the Alta intake has the front Grille diverter tube going....i cant see any port like on the Craven Speed...How does this intake take advantage of this diverter? I have read that it does but how?

What about intakes...everybody has their favorite....should i go with something else?

 

The factory intake remains since the bottom of the stock air box remains intact. I have the Alta and I personally think its the best cai available for the R53. Its well made, isolates well from the engine compartment, retains the stock front air intake and is completely open to the cowl vent. And the sound….!

 

Are you going to get the cover for the cai, or just hope that the hood seals it from the top?
second thing to consider....the plastic panel behind the airbox by the firewall...
Some folks remove it entirely, some use a hole saw to swisscheese it to help airflow/sound flow. Since it sounds like you WANT more sound, something to consider.
I went a different route for the cai, but the ALTA is very popular.

 

The intake tubes...are mostly for looks. If the feel the inside of the common silicone ones, they are actualy ROUGHER than the molded oem duct...for a hp gain imo, look elsewhere, but installed right, they are a nice enginebay dress up item, and can add a bit of color....one tip...they usually reqire a bit of trimming where they connect to fit right, and not slip off, so a used one may/maynot fit ok.

 

I had the Alta CAI and it does in fact seal to the hood. The problem that I have is that there is about a half inch gap on the battery remote connection side between the CAI and the factory lower air box. I currently have the DDM CAI and have a far better seal the the lower box, and same sound and air from cowel area. The reason the gap is a problem with the Alta Cai is it sits right over the exhaust header and sucks alot of heat in IN MY OPINION. I still use the Alta silicon tube from my old CAI on the new one. Prefer the silicon tube to the stock one and had it left over from my Alta cai.

 

For intakes, the choices are becoming limited...espically as the cars age and producers stop making parts...i have a dinian intake...good isolation, just a bit more sound than jcw (good for longer trips), and looks oem...it is molded plastic, is a new top, with a new cone filter, an adapotor, and a modified snorkel that connects to both the front, and a second one that is by the front of the driverside window. Used ones, new stock appears sometimes, but it is out of production like many mini parts....

 

The rear plastic panel is removed completely for the Alta. The new sides seal very well against the hood for isolation - you can see the indentation in the hood insulation mat. If installed properly, there are no gaps...

 

On an R53, the unit doesn't sit over the header. Maybe OP should clarify which model/gen they have experience with. I have heard there may be better choices for other models.

 

Not sure if I am correct but I think the header is , when looking at the motor from the front, on the left side. Alta's CAI sits on the top right. The tube they supply in the kit goes down to the intake manifold I believe. Also I cut out the separating piece under the cowl vent to fit the box. Everything seals up under the hood and the cowl vent acts as a vacuum for the intake. Great noise and even better with a pulley reduction. I have more pics if you need them.