Spacing between CPU cooler and PSU

Solution
It really depends on the airflow. You typically want air to come into the case, pass over the hard drive(s), pass over the motherboard components, then the CPU heat sink, then exit the case. Since most PSUs have fans oriented to vent air out, exhausting the CPU air directly through the PSU is acceptable in that configuration. Unless your CPU tends to get very hot, in which case you probably want to vent CPU air directly out of the case using a duct. That way the PSU only gets air which has been heated by the hard drive and motherboard, not by the CPU. (Most GPUs vent air directly out of the case.)
Yeah that's a definite no on the cpu cooler. If you want it to be effective, set it horizontally, with plenty of space for air to be getting in. What case is that? If you're hitting your memory sticks, either get a different, lower memory (try corsair vengeance) or try the NH-U14S instead of NH-D15. Few degrees difference in temperature but no memory clearance issues (unless using all 4 sticks, check this in advance). Also check that its size in specifications on manufacturer's page fits your case. That's to check for any cooler but noctua will also list you a table for every single motherboard combination with their individual coolers, and what's likely to not be fitting.
 
It really depends on the airflow. You typically want air to come into the case, pass over the hard drive(s), pass over the motherboard components, then the CPU heat sink, then exit the case. Since most PSUs have fans oriented to vent air out, exhausting the CPU air directly through the PSU is acceptable in that configuration. Unless your CPU tends to get very hot, in which case you probably want to vent CPU air directly out of the case using a duct. That way the PSU only gets air which has been heated by the hard drive and motherboard, not by the CPU. (Most GPUs vent air directly out of the case.)
 
Solution