I would have to say it will cool that system fine. 2.7Ghz is not much of an overclock, and as you saw with my testing results, 3GHz was running 65C or so which is well withing the acceptable temperature range. I would expect you to get the same or maybe even slightly lower temps with the PURE.
Intel E6300/Nouctua NH-9U w/dual 92mm Panaflos
XFX 680i LT
Patriot PC2-6400 2X2GB LL
2 X BFG 8800GTX in SLI
Enermax Revolution 620W PSU
ASUS 24X DVD/Seagate 250GB SATA 2/THermaltake A90/Windows 7 Ultimate 64