I'd save your money and get a PSU with a big fan then. That PSU will take the case heat up, making the average temperature hotter and forcing all the other fans to blow harder. You'd be better off getting a PSU with a temperature controlled, 140mm fan and spending some of the extra money you saved on high quality fans which you can use a cheap in line fan controller cable to make them spin slower and sound quieter I like the idea of the fanless PSU, I'm just not sure if it'll actually help make your PC any quieter.

You'll only need a 3rd party CPU (processor) heatsink - the Asus one comes with a well reviewed one and changing the GPU heatsink can be very fiddly + voids the warranty. Chipsets don't put enough out heat to need anything other than passive cooling with help from the case fans. Noctua are the best quality but they aren't cheap; you're talking $80 to $90 for the CPU heatsink, which seems overkill to me. That said, the fans are great quality, and one like this:

Newegg.com - Noctua NH-D14 120mm & 140mm SSO CPU Cooler

Would be ridiculously quiet and remove the need for a back fan on the case, so you'd just need a single fan for the front.