Hi. From what I've hear oil coolers suck, stick with big heater cores if possible. For the blocks, I would go with
D-TeK's sidewinder or spir@l, or if you don't want to buy their stuff you could go with
dden's maze3. you can get a heater core online from
www.heatercore4u.com. As for a res, the more water the better. So if you're going for a rack mount and you have an extra rack available, you could build a res out of plex and mount it above the computer. All you really need is a jig saw (or any saw) and some glue (rv silicone?).