OP, if it were cheapskate me, I would look for the intake hoses on
RockAuto.com. I have no idea if they carry them, but you can search there. I will say that I have always been very pleased with their selection, prices and customer service, and I have bought a lot from them.
Regarding the intake, I wouldn't piss away any money on that, unless I just had extra spending money burning a hole in my pocket. As others have said, there isn't much to be gained there.
I did the deckplate mod 10 years ago. Because I like screwing with stuff, and because it was cheap to do. However, I can't really tell any difference at all in either power or fuel economy. If I could seemingly tell a difference in power, it would likely be the placebo effect. Louder almost always sounds and "feels" more powerful, especially if you are wanting to justify and rationalize what you just did.
As an aside - I found that out with offroad motorcycles, when I used to ride. If I were to ride again, I would never, ever put a loud pipe on a bike. Those are obnoxious. To everyone. On my DRZ400S, I took off the loud pipe that came with it. I opened up the intake (because the horsepower on that bike
really is limited by the intake, and not the exhaust. I also put the stock pope back on. And guess what? It was no longer obnoxious. It was very quiet, and it had every bit as much, if not more, power than it had with the fart can. And I didn't piss off anyone when I rode, nor did I need ear protection.
Back on track - the deckplate mod gives it a throaty sound. Not obnoxious at all. But as I understand it, the ECU adapts and makes changes to things based on that, so you really don't gain much, if anything real, from doing it. If I don't foresee crossing deep creeks or driving in a hurricane, I leave my deckplate plug off, just to rationalize and justify what I did. So that I didn't waste my time and money for nothing - lol. If I foresee a bunch of water maybe going up into my engine compartment, then I put the deckplate plug back on it.