Hi have Audi a4 quattro with a 2.8L engine and the first thing I wanted to do was add a K&N cold air intake and wanted to know what if there are things to look for when installing and set up or is it just like plug n play?

 

The K&N cold air intake will likely do diddly squat for making any more power and if you get a little too much oil on the filter, it will mess with the mass airflow sensor (MAS) and actually make the engine run worse.

The stock airbox from the factory with a fresh Mann paper element in it will easily flow all the air the 2.8L V6 is capable of inhaling, plus at highway speeds it even gets a bit of ram induction effect. Yeah, it lacks the "cool" factor of a K&N or other brand of similar cold air intake but it functions about the best you can get on a daily driver car.

There is not much out there in the aftermarket world for souping up the 2.8L V6 engines. There used to be a supercharger kit for $3-4K that would add maybe 100hp but I don't believe it's on the market anymore. There are also some ECU reprogramming options ("chipping") that yield dubious claims of a few more horsepower.

Here's a website that sums things up for the 2.8L V6 engined A4's.
Fourtitude.com - The definitive b5 a4 2.8l performance mod thread

Basically our cars with the 2.8L were left behind by the aftermarket performance world, except for suspension and handling mods.

 

ECU tune