Does anyone know if I would be gaining anything more by dropping in a K&N filter into the stock air box or a Cold Air Intake like K&N Typhoon 69-2004TTK.

 

Yes, better sound.

 

^This. I agree with post above. The blow out valve is more audible and the car sounds throatier on acceleration, but could just be the stock "sport soundmaker". As far as gains in HP etc. I couldn't say, I bought my 2010 MCS with it already installed along with a JCW strut bar so I don't know how the stock box handled. However, my smog shop always mentions that it's not best for emissions, but the car always passes anyway. I've replaced the filter once, don't have issues in damp weather either, but I'm in SoCal. You can hear the BOV in the video below just for reference at the 0:27s mark (on an automatic, I assume it's better on manual).

 

I've removed the sound maker on mine and I do like the sound of the open air filter system on mine but it's not the one pictured.

Performance wise probably nothing in it to be honest compared with a standard box and performance air filter.

Buying higher performance tires will give you more..

 

I have the typhoon on my '11 SJCW (It was installed by owner, I sold it to, before buying it back last year). I am impressed with the sound, I don't think it is helping with MPG and may put the factory JCW airbox back on this spring.

 

Why is this called a "cold air intake"? You are opening the air filter to the engine bay and negating the effect of the existing cold air intake from the front of the engine? I think if you want a small boost, the way to go is the AEM cold air intake. That is probably the direction I'm going with. Since it is a real cold air intake system using cold air from the ram scoop as well as the existing cold air intake pipe, it makes more sense to me. See https://www.aemintakes.com/21-699c-a...-intake-system

 

It still gets cold air from the bonnet scoop and OE cold air duct.

 

We always recommend going with a dry filter so no oil goes in the sensors.
https://www.waymotorworks.com/dry-pa...-cooper-s.html

Running an open intake like the K&N just sucks hot engine air and won't actually gain power.

We do recommend removing the noise maker and the resonator to improve airflow through the intake system.
https://www.waymotorworks.com/wmw-no...5-r56-r57.html
https://www.waymotorworks.com/wmw-re...7-r58-r59.html

If you really want an intake you can do the AEM intake which has the duct from the scoop to get more air to it.
https://www.waymotorworks.com/aem-co...-cooper-s.html

 

I don't think so. When the air filter is closed in, it "MUST" suck air in from the outside because of the pressure differential. Here the air box is open, and fully exposed to the engine compartment. The only thing you are going to do is suck hot engine air. The OE air duct becomes mostly defunct without a pressure gradient. The bonnet scoop is mostly blocked as you know.

With the A&E, you remove the restriction on the bonnet scoop. You add an attachment that "forces air" into the air box. The air box becomes "closed" like OE. So now air continues to come in from the OE duct as well as the rammed air. Then, you reduce air restriction with the filter which the K&N does as well.

I think you'd be better just with a performance filter and saving your money--should be mostly equal.

AS WMW says, my plan is to eliminate the muffler and add the A&E. Even then, you are going to start to hit the limit of the stock motor. You likely need to fix the exit/muffler at that point and get a tune.

 

For better sound I would recommend the open air intake, this is what I have

http://www.gtt.uk.com/product/mini-g...induction-kit/

I'm ignoring all the power gains marketing stuff it can make and purely basing it on sound. Although cheaper can be acheived by just using a cone filter like the JDM cars people use.

For performance the AEM intake system will be best or similar product.

Bang/$ would be what WayMotorWorks recommend performace dry panel filter inside OE box.