I have the p5bdlx and have had my PCI-e set to 114mhz since I got it. No ill affects or issues, and I gained another 15mhz from my gpu clock speed. Even before I got this mobo, I ran my 7900gt at 112mhz on my other mobo.
So- no, I would say, it will not do any crazy damage, or decrease the life of your card beyind what any normal OC'ing will do. My 7900 has run at 650-680mhz core at 1.4v and 114mhz PCI-e for a year straight now. This rig is on 24/7 for folding use and only gets one restart a week. If that doesnt vouch for it, I dont know what else to say.
*114mhz also gave me my highest ever 3dMark06' score of 6910...not too bad eh? Give it a try, use something like AM3 for testing. If you do set the pci-e too high, your screen will go black...just reboot. nbd.