I finally got a USP and now I want a rifle but don't have alot to spend. I've seen the Century CETME rifles for sale often for $500. Is that a good price for those? If so is it possible to put say this: http://www.hkparts.net/shop/pc/viewPrd.asp?idproduct=1515&idcategory=8 on it to make it more authentic? I don't know anything about this stuff but I'm sure most of you. I know I have to keep the US made parts to a certain level. Also are the Century guns made from real G# surplus parts and which ones could I easily replace to make it less American Century junk? Thanks!