It would be nice to go into things n00bs get hung up on (or more often make mistakes with), such as mixing up tube diameters or buying an external system with a case that doesn't have holes in the back for tubes. Maybe provide a picture of a shorted ATX connector, as well, for those unfortunate souls that might find the wrong instructions online.
Also, the MB PWM is often neglected with water-cooling, and takes a beating in an overclocked system. Inverting the ATX case fan next to the CPU is generally a quick-fix, or even just adding after-market heat sinks to the regulators. Either way, it's important to watch the PWM temps on the motherboard when overclocking a water-cooled system.
There are a lot of cheap system to stay away from, such as thermaltake's bigwater, which has a short pump-life, and is NOT covered under warranty (When the pump goes, you buy a new system).
What about putting the splitter before the CPU? The GPU tends to get the hottest, and benefits the most from very cool water. What about sound levels? Can you put a db meter up to the new system versus the old?
Just my 2 cents.
Thanks.