Which has probably been asked but I couldn't find an answer... I have a stock WR exhaust that is bored out from the PO and pretty loud. Would like to quiet it down and not suffer much for power loss so I'm looking at going to the YZ exhaust. 1. Is it worthwhile to get the full exhaust (including header) off a YZ to get the most benefit? Not sure if there is a difference between YZ/WR header flow/design. 2. Does the YZ exhaust have an OEM spark arrestor? If not I assume I can modify something to fit? I'll need one for some future group trail rides. Thanks.