XS Sight Rail, Brownell's
I purchased said item for Scout Rifle from Brownell's and I don't recall any inordinate custom fees. Anything in stock I order from them takes about 8-10days.
Last items ordered were poly 10 rd magazines for the Scout. They were backordered. Brownell's provided a backorder notice for me and about 3 weeks later, I recieved them paying duty at the door.
All in all, Brownell's is ok. Once when they sent me rings for a Ruger #1 with one ring missing the top half, they sent me a new whole set after I emailed (politely). But another time a front sight was shipped being the wrong height, but I didn't grouse about that. Not worth the bother.
As for the XS rail, I like it on my Marlin Guide Gun. Great kit. On the Scout, I removed it and went back to the stock forward rail with a Leupold Scout Scope. I tend to use low power scopes anyway and the XS rail on the Scout blocked the reciever port too much. I could have milled it out a bit, but then other issues would arise. For me, and the rifle's purpose as a hunting arm in Northern Ontario, it suits me fine.
Good luck, keep safe and consider backordering the rail. Fall is getting close.