I changed the fuel filter on my 99 Sei sporting and the thing goes like a train now (well sort of ). I suspect mine was the original as I could barely blow through it so it must have been really bunged up. The difference is amazing, it pulls much harder throughout the rev range and it now loves to rev while before it was breathless at high RPM. If you don't know when you fuel filter was last changed then do it, you won't regret it .