turbo boost will not
damage your CPU... look at it this way, its like the NOS system on a drag car. It'll give you that boost but it isn't sustained for a long period as opposed to OC, which is like a race car designed for a race track (for as many laps needed).
btw you won't see much improvement with that turbo boost feature, if it did wonders for so many people, than the aftermarket cooler industry would've gone outa business as enthusiasts wouldn't need to OC their cpu's at all.
* wait out and see what AMD has to offer with Bulldozer and with Intel's SB-E
** since you have an i5-750 I'd advise getting something another year from now...(look up my member rig 2 and you'll see what I'm playing/working on)
*** in the mean time, ask your buddy what cooler he gave you (and post back) and then do some OC'ing if the cooler checks out - could be you already have a Hyper with you