Here is the rack extender that I added. I like this set up. You can get the Paris box for close to or just over $300. I was going to have to order it and it wasn't going to get in until after I needed it. We are riding on the fourth so it would have sucked to been without. I got that box for $150 and the rack was $85. I did have to strap it down because the mounting instructions required rails for it to be mounted to and I don't really have rails to accommodate the u-bolts it came with. Either way there was some type of drilling to mount it and I saw that one more way for water to creep into the storage area. I know it looks sketch but strapping it down works best for me. Though it is nice that the Polaris unit has a quick fasten and release system. the Kolpin box offers a lot more storage since it is holding 2 helmets. You can't even get one helmet in the Polaris box with a visor. We tried it out and my wife likes it!