From people's posts and the Google Doc, seems that the most cost effective cooling solution is just the NH-L9i/a with custom fan duct.
I'm using the LP53 with nf-9x14 and a rubber seal between it and the case vent. This is the best configuration I have found. I always use a shroud, duct or a seal between my fan and case. Drops temps immensely and creates positive pressure to force out warm exhaust.