I bought one for my 2006 rmz 250 a while ago and I had to drill holes and rivet the end cap on which did a great job but wasn't super easy and hassle free but it sit the job and works great. I bought one for my 2008 rmz 450 last week and it was VERY easy to put on. It didn't come with bolts for the end cap to bolt to the exhaust which confused me at first but when I went to put it on, I used the stock end cap bolts. The holes lined up perfectly so there wasn't any drilling. It went on super smooth and looks great. There expensive but it's cheaper than getting a new exhaust with a spark arrestor and if you ride trails or dunes, you have to have one, so it's worth it.