Hey Buff, I have a '99 KX-250 with the V-Force Delta Reed Cage installed. It made a huge difference everywhere. The bike has plenty of bottom and mid, but the V-Force really brought it to life. The best way to set the reeds is on low tension. The throttle response is awesome. If you set it on high tension, it will not pull any longer and you loose all of your responce down low. The '98 has the same power characteristics as the '99. It is a bottom to mid motor and you are not going to change that. However, the V-Force definitely enhances the power. Definitely worth the money.