Any ideas for tubing (red), fittings, and radiator?
For a budget, try this. Full CPU Kit Extra Tubing GPU Block
Updated with URLS
BTW, the kit comes with clear tubing-maybe go in Red, out Clear? It's up to you, just an idea
Edit 2: Forgot to mention, the fittings are custom to your build. Last thing to get, after you plan how you'll assemble it, so you know which and how many of what angle fittings you'll get. Try to match em with the kits, and also make sure they're the same for the tubing's sake, if you get to small fittings-well that'll be catastrophic. And too big will usually not fit the tubing onto it, some people heat the tubing to warp it on...not recommended by me.