Hey everybody this is my 1st post. I have a 2000 xplorer 250 4x4. I am beginning to wear down the AT489's that came on it and am in the market for some different tires. I avoid the mud if possible. I mainly trail ride and am beginning to get into some jumping. I would like to get a little more umph from the start and was thinking about going to a slightly smaller tire(front and rear). I have 4 main questions. 1) How much top end speed will I lose going to 22" rear or 20" rear. 2)Will there be a noticable difference in acceleration with smaller tires. 3)Are the Titan Fast Trekkers a good tire? Thanks for any input.