On the sl65 has anyone installed K&N filters and do the make a difference?

I am not sure K&N makes a filter for the V12 TT engine (they didn't last time I checked last year). BMC makes drop-in filters for the V12 TT engine. They usually run about $180-$200 for the pair. Alternatively, you can cut up a Green Filter to fit the airbox. An aftermarket air filter can make up to 10hp more on a Dynojet.

Tom

K&N now makes a specific application filter for the V12TT. I purchased a pair (they are packaged 2 in a box) from Kragen for about $96. They must be special ordered as they are not stocked in the store. It took two days so they must be held in local inventory. I put them in the SL600, but not yet in the S65. I could not tell any difference in street driving.

I run K&Ns in my race cars. But I also rebuild those motors fairly regularly. I don't run K&Ns on the 65 as I believe I get similar flow and better filtering from the stock paper filters.

We use K&Ns where available in most of the cars we tune and there is a noticeable difference in performance.

but not really any performance difference. I haven't tried the BMC's though lots of folks think it's good stuff. .

I've used K&N is past, and they produce more power, longer. However, a clean, new OEM filter produces same power, clogs faster, but filters better.

I now just change my OEM air filters more regularly.