Don't have an answer for your main question, but just to give you a little more headache; make sure the Tuniq fits your motherboard as well. Some of the newer northbridge heat spreaders are fairly large, and the capacitors can get in the way as well.
Btw, I'm also planning to OC the E6750 to 3.2GHz, but I'm going to try stock cooling first. These chips run pretty cool, so I would hold off on the Tuniq until you know you'll need it.
Also, take a look at the Antec 900 as well (just a personal note).