I got my 08 g35x about a month ago and just realized that it has K&N filters. This seems a little weird since it was a lease vehicle previously. My question is, if I get rid of them will I notice a performance decrease? I don't think I'll have the motivation to clean them and I've also read they don't filter quite as good as the stock paper ones. I've read they can give 1-5 HP but I'm not sure if that's true and also whether I would even notice that.

Thanks

 

I don't think you'll notice, but I'd keep it and get the cleaner system to re-use it instead of replacing it with a lower quality one.

Get a Ztube and plenum spacer and then you will notice some power improvements.

 

^he's in an '08
Ztube and plenum spacer are a no-go.

They probably got missed on lease return.
If you replace them you will hardly notice a thing.

 

what he said.

 

Thanks for the replies. Is there any validity to the concern that these filters increase airflow because they don't filter quite as much as stock ones, and therefore there is more junk getting into the engine?

 

I would have to say that's false.

 

Reallyy??? No plenum spacers for VQHR?

 

Yes there's validity to that.

Does it matter enough to harm your engine? No.

Another possible issue is over oiling a K&N can gum up some of your intake sensors.

Bottom line: K&N can save you money long term if you don't mind oiling your own filter. Power increase/loss is nothing anyone could ever notice.