I'm not sure the % burn would have much to do with how dirty your gas system gets, you could try it and find out. If you don't like the Re15 you should be able to swap it for something else easily enough. I haven't seen Re15 available for a long, long time and I know there's lots of folks who would love to get their hands on some.

Don't be the darkness.

America will perish while those who should be standing guard are satisfying their lusts.