I got pretty much all my pipework/hoses from autosiliconehoses.com via ebay. It taken a bit of head scratching working out the lengths and angles for the bends etc

I would say you really want the coolant temp sensor in the engine rather than in a hose, I fitted my cvh temp gauge sender into a adapter in the top hose though as I wasn't sure on tapping/drilling for a tapered sensor.

There is a upgraded rst s2 aloy rad on ebay I've heard good feedback on.