So my original 357xp bought in 07 had the plastic clamp and the walbro carb, this one is the updated model with the zama carb and metal clamp, also i believe they mad some adjustments to the intake shroud for fit. Additionally, it does have the manual decompression switch. Not sure about the muffler or how to tell if it is a cat muffler looks fairly standard. Just did some digging around and it seems like that can cause it to run hot so maybe that was my issue. I will do some more reasearch on it and let you know. Thanks.