Questions: 1. What is a tach sensor? (Mainly the one on the Swiftech MCP655-B, the one without the speed switch.) 2. What would be a good AM3 waterblock? (I've looked at the Enzotech Luna/Sapphire and some of Swiftech/dTek's offerings.) 3. Are there any downsides to having a bay reservoir? 4. Does the size of the res matter? 5. Are pumps/reservoirs/radiators "tube size" specific? 6. To run more than one loop, what extra parts would be needed?