A lot of large distributors have private label lines of their own produced overseas at a lower price point to offer a option to consumers at a price point lower than flooring from the Big 4 manufacturers. The large manufacturers have so much tied up in marketing their pricing is much higher but private label lines are often marketed only as an alternative to the brand names at a lower price point. I'd guess that is what you are looking at. The distributor most likely carries the warranty themselves. This isn't necessarily a bad thing, as many times the off-brand quality can be as good as the brand name products, you just have to make sure they stand behind it which is what you are doing. I'd ask the retail store what their experience has been in dealing with claims from product that comes from Golden State.

You need to do a little more archeological digging still. You need to know the whole construction of the floor before you can decide how best to install something new. I'd take up that plywood piece in the kitchen and see what's under it. It's higher than the surrounding floor, so needs to go. You should also be able to see from there what subfloor is under the original kitchen hardwood. It's too bad the space under your entryway is finished, but I'd still do some exploring from below to see what's under there, and to figure out the fix to stop it from squeaking. Is it drywall below or a drop ceiling? I know it probably seems like a pain to tear out drywall, but if you cut out a clean patch, like 2' x the width of the joists, it'll be relatively simple to repair. Just make sure to cut it down the center of the joists so that there's room to screw the patch piece to it later. Cut the hole under the area that squeaks the most, if you can. Have someone walk on and watch the floor from below to see what's moving. It might be as simple as pounding in a couple shims from below, or face-nailing a loose board from above. You want to find out what's underneath the hardwood. It might be laid directly on the floor joists, or there might be 10" wide boards that the hardwood is nailed to. Another thought is to take out a board in the hallway, since that's not original and you want to replace it. See what the subfloor is there. I am a bit puzzled at why, when you've stripped the kitchen down to the original hardwood, it's still higher than the hallway floor. Is your current surface perhaps not the original kitchen hardwood? Peeling back the plywood area will help determine that. BTW, I haven't heard of that stop squeaking product you linked to, so can't offer any personal opinion. And don't pour self-leveling compound over top of hardwood. It needs to go over plywood.

Redroze, I'm just getting back online and seeing your questions, so I'll try to answer what I can. My new floor in the LR/DR was not pre-finished, it was all site-finished. I did put a pre-finished floor down in my office (no pics, sorry) because I work from home and didn't have time to be without my office for the week it would have taken to have floor sanded etc. The pre-finished does have a different feel to it than the site-finished. I wouldn't say it's grooved, just a more defined difference in between the individual planks. The office doesn't adjoin any other room, except the tiled hallway, so I didn't worry so much about the wood being different there. I see from your pictures what you mean about running the planks the same way and wanting to be sure things don't look odd. One idea might be to take up some of your FR planks, like the first 12 or so, and then put them back down interwoven with the new planks. That way there's not a clear line in between the 2 rooms, but rather a more gradual blending. Here's another couple of pictures, this time of my family room. The first one is a before shot of the hardwood floor + a rug-like carpet. The floor created a frame around the carpet. I had the carpet taken up and new hardwood put in where the carpet originally was, then everything sanded and refinished. You absolutely can't tell where the old wood was vs where the new started. In this case, the new is random width because it opens directly to the kitchen (as opposed to the LR/DR which is all the same width). So, one house, all new site-finished floors in the LR & DR, all new pre-finished floor in the office, original/refinished in the kitchen, and half&half refinished + original in the family room. Boy did we have dust! Hope this helps! New:

Only the completely uninformed would do that. It creates tons of problems.