Hadda run last night and do "daddy taxi" .... so got off work, had to pick him up.
-If ya going to WC....the most important decision to my mind is picking the right chassis.....not only for ya current but as well as ya future needs. If you start out with a CPU loop the Corsair 500R is a great choice .... If ta later wanna do tri-SLI, that ain't gonna work and you'll be wanting a 900D or maybe even a Case Labs. To my mind the best WC chassis available right now at a moderate price ($25) is the Phanteks Enthoo Primo.... holds 15 fans, up to 5 rads .... and the feature list is extensive....reservoir bracket, pre-drilled pump mount..... takes a lot of the DIY outta the equation.
It also comes with (5) $20 fans and a fan control PCB which gives ya PWM control of 11 fans without the expense of actually having to buy PWM fans.
-Do the math .... rules of thumb are just that. Calculate ya total TDP for items being cooled
CPU Processor: 60-150W
Single GPU (low-end): 100W
Single GPU (mid-range): 150-250W
Single GPU (high-end): 200-350W
Voltage Regulators: 5-20W
Memory: 2-5W per stick
Hard Drive (regular or SSD): 10-30W
You can use the Temp / PSU Calculator for the overclocked CPU (either one gives same answer)
A good source of rad heat numbers is martinsliquidlab.org . In short, using the best rads in his tests with single fan in push ..... (based upon 60mm thick Alphacool)
Each 120mm of rad will get @ 50 watts of cooling at fan speed of 1000 rpm
Each 120mm of rad will get @ 63 watts of cooling at fan speed of 1250 rpm
Each 120mm of rad will get @ 70 watts of cooling at fan speed of 1400 rpm
Each 120mm of rad will get @ 90 watts of cooling at fan speed of 1800 rpm
Each 120mm of rad will get @ 109 watts of cooling at fan speed of 2200 rpm
Each 140mm of rad will get @ 69 watts of cooling at fan speed of 1000 rpm
Each 140mm of rad will get @ 85 watts of cooling at fan speed of 1250 rpm
Each 140mm of rad will get @ 95 watts of cooling at fan speed of 1400 rpm
Each 140mm of rad will get @ 122 watts of cooling at fan speed of 1800 rpm
Each 140mm of rad will get @ 179 watts of cooling at fan speed of 2200 rpm
Add 21% (possibly up to 30%) in push pull.
-pick a CPU WB that is best suited for your processor platform
-If you plan on water cooling ya GFX, make sure they make a block for your card before ya buy one..... reference cards are easy enough but I'd recommend the non-reference card for the custom PCBs and beefier VRM ....but not very vendor will make a card for this market and if it's old card, might be outta production.
-Kits are a nice introduction but they just about all contain bay reservoirs .... many don't like them cause they rattle and others have reported leaking seams which vendors have blamed on use if ethylene glycol on acrylic .... well not so much as the acrylic (tho microcracking has been reported) but the glue used in the seams. There's significant debate on whether this is 'real" or not but that kinda doesn't matter if vendor's warranty policy is voided because it prohibits such usage.
-Pumps are prolly the most difficult choice for most..... res mounted pump is convenient but for example Swiftech voids the warranty on pump if reservoir was attached. There's everything from the 35x2 which I could prolly use for my lawn sprinkler system down to pumps I wouldn't trust at all..... too much really to go into in a short post but the sticky has lotta info.
-If ya gonna buy a tube reservoir and fill from the top, make sure to get the optional multiport top and a fill tube