just put a K&N stage 3 jet kit in my 2000 DS650 tonight and it is unreal... before I was just runing my aftermarket exhaust cap and I noticed a good low end gain from that but this is crazy... my cousin has an 03 Baja and before this we where dead even but after the install we raced and there was no comparison.. I let him take off first then I nailed it and walked right by him... definantly the best mod I have ever seen on any one of my quads...