Been following 919s since I bought mine new in August 02. Honda new model releases with year-year changes, Motorush, Hornet's Nest, & WT. 06 was an across the board EPA change year in the US. Both 49 state & CA upped their stds....basically the old CA regs became the 49 state & CA got even toigher. SImilar to how now most bikes are global & folllow the Euro 3/4/5 stds. 06 was the year all the two strokes died in the US accordingly. Banshees, PWC, dirt bikes became closed competition only or disappeared all together. A similar purge just happened due to the change to Euro 5. Bye bye CB1100, FJR1300, et all. My 02 49 state had a black Y stock but I wanted a SS Y so I put one on less the cat since my bike never had one. No point in a black painted Y between SS headers & Satos. The cat is a restriction which causes heat gain & thus requires SS to not cook the paint off. I have several posts on this topic, one that includes part numbers & you can follow those not only thru the Y's but also ECUs. Janet's fitting of a cat Y to an 02 officially sanctioned by Honda in the UK is a story of legend & documented on the Nest. True David & Goliath.