Use 1604-195 / 1604-195 .460" diameter rear springs (1998 ZR440 SnoPro style) and the 0604-685 front arm spring. They are much stiffer than stock and came standard on the 1998 LE XC 600's and SP 440's. You will have a tough time getting these springs to bottom. Also, you might want to consider the 1998 LE XC rear shock valving with the shorter shock control rods. It creates the "bottomless" rear suspension and isn't too bad to trail ride, either.