I replaced my standard OEM air filter with a K&N direct replacement. After eventually getting the screws undone to my airbox and emptying all of the dead flies and leaves out of it (car has just been sevices by Peugeot and I find it hard to believe that so many flies and leaves have got into the fiter system so quickly, the lazy bastards!) I removed the OEM filter.
The K&N direct replacement filter is a lot smaller in depth (I assume for greater airflow) and fits nice and snug in the airbox.
Re-fitted the airbox bits. Took the car out for a spin today, and my god its awesome.
You can instantly feel the difference, the lower end power and acceleration is greatly improved and, there is a slight increase in engine roar as more air is sucked into the engine.
Best £40 I have ever spent, and I will never need another air filter ever again.
Not sure about my fuel consumption, whether it will improve (as I was informed) or whether it will drop, but who cares, it sounds great and goes awesome!
Along with my now regular use of Shell V-Power it has made a huge improvement. Next i'm going to replace the spark plugs with Bosch Super 4's and put on a Scorpion performance backbox. Im also gonna see what else I can replace under the bonnet for small power gains.
Buy One!
(Oh forgot to add, my 406 is obviously a 2.0 Petrol so it might make a difference what engine you have and what difference you notice, but you knew that!)
Pris.
)
and very well made I might add.
I might have to bend the truth on how much it costs though.
Genious 
