- PA120.3 (or equivalent rad space) - You want at least 3x120mm radiator space for cooling CPU and GPU. More if you plan on adding more later, but worry about that then; this is right now.
- MCP 355 with XSPC or Bitspower reservoir top. ~$110
- EK Supreme HF - CPU block ~$80
- EK FC480 - GPU block ~$110
- Tygon 3603 7/16 x 5/8 - at least 10 ft. $1.95/ft. More if you want some wiggle room.
- Bitspower 1/2" Barbs - ~$3/per - You'll need 8 (two on rad, two on cpu, two on gpu and two on pump/res combo)
Now this is where it gets fun. People are selling stuff here on OCN and on other forums all the time so I'll bet you can find the radiator, pump/top/res and barbs all for a lot cheaper. Also, you've already got the h70 which is *technically* watercooling... If you cut off the EK Supreme HF that saves you $80, plus fittings and the extra tubing it would take and even extra rad space if you want to get only a 120.2 right now.
Yes it's an expensive hobby, but the gains are freakin' sweet.
You'll continually want to do more and the rabbit hole goes deeper and deeper. Start small, and start with some used stuff... that will cut your costs down a bunch.