Wix filter for twin cam used in an evo ??? Wix filter #51438 is for twin cams (1999+) and has a 24 micron element. Wix filter #51215 is for evos and has a 21 micron element. Other that this micron thing, the filters are identical. Is this difference significant. or can I use the twin cam filter in my 1992 FXLR (evo low rider) ?