I 've never ran a 98 but it seems that the 9660 STS's power is the perfect match for the rest of the combine. In wheat we start to lose too much out the back before we lose power( more hp=more on the ground). In corn, 200+ bu_ac, 8 row at 6.5 mph I've still got power to spare, but the clean grain elevator can't handle it. In rye which is 5 or 6 feet tall, at times I will run out of power but if it's really heavy and down the feed accelerater starts to chatter and growl like it's about to plug. So from my expierence more power is of little or no use. I've heard this fall that some local 9860's in really good corn were smoking belts on the clean grain because they were getting backed up with corn.