You could remove your belts one by one to see if the sound goes away. Could be the timing belt though. Also you can check for exhaust leaks, mainly the exhaust manifold studs.
The part number is 11026-01M02-
http://www.ebay.com/itm/Set-of-10-Nissan-Oil-Drain-Plug-Crush-Washer-Gaskets-11026-01M02-/160648840409?pt=Motors_Car_Truck_Parts_Accessories&hash=item25676ac4d9&vxp=mtr
Yeah, my thermostat must be stuffed then. I wouldn't run the car while flushing and I'd let it cool right down before flushing because of the sudden temperature changes.
Don't forget to do the heater core aswell. Also put the hose in both front radiator hoses plus the two from the heater to the engine. Keep repeating till the water is coming out clear.
If you have 12mm bolt holes R33 gtst brakes are what you want for direct fit.
http://www.skylinesaustralia.com/forums/topic/292492-fyi-r33-gtst-brake-upgrade-on-a-r34-gt-non-turbo/
http://www.skylinesaustralia.com/forums/topic/316208-help-a-twat-understand-r34-gt-brake-options/
http://www.skylinesaustralia.com/forums/topic/213441-na-r34-brakes-and-rotors/
Same part number for front hinges on all r32s. Top and bottom are the same part number. Sedan front doors same part number too. They are side specific though.
Left:
80401-01U00-
RIght:
80400-01U00-