well all the stuff i did to get the mpg is in one of my post on here. i use distilled water and koh which adding koh makes amps in the gen, more koh more amps up to around 20 or so total using electrolysis. the scan gauge lets me check all my sens to see what they are running at and if they are doing what they are supposed to be, on top of that it let's me know my mpg as i drive which knowing that you can even increase your gas, kinda like a teacher showing you how to do it the right way i guess (poor example, but i'm tired). the gauge is worth it wether you have anything or not, knowing everything about your vehicle is priceless. the tire thing is pretty good also, but such a pain to experiment with. we've had the unit on the crv for about 3 months, then finally got our gauge, and after leaning it out we are about 60 avg. mpg. didn't lower the vx, probably not going to. gotta remember though about bigger tires slower speed, smaller tires faster speed, even though the speedometer will be off, in my opinion it takes more effort to move something bigger then something smaller, kinda like a underdrive pulley. we might buy a map sens enhancer so we can adjust rich to lean from inside the vehicle, makes it so much easier. i think i'm gonna pimp out the vx with 45" amish wheels lol.