I have done and still do the acetone in my car. It had no noticable effect on my MPG, however I did notice an increas in power.
As for K&N, screw that! K&N sucks big balls, if you have a K&N on your car you might as well take it out and leave it open.
This is an independant studdy on several filter brands, including K&N.
This study proves that,
-K&N lets an enormous amount of dirt through
-K&N has negligable increase in flow (especialy at the rates that most of our engines run)
-K&N is more restictive than other brands as it gets dirty
And that in general K&N sucks. If you want a filter get an AC Delco filter, that is 150 times more effective at dirt removal than K&N, and does not require rutine mainainance.
http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
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86 Crown Vic
Crate 94-95 5.0L HO EFI, 2-1/2" cat-less dual with DMH e-cutouts, 4R70W AOD, 3.55 Detroit TrueTrac, and much more!