what i did with my MSI R5770 Hawk was took off the stock cooler, removed the crappy stock TIM, applied MX-3 and while it was apart i added Enzotech BCC9's to it. i have had this card about a 1.5 months and really been running Boinc about 3 +/- weeks and i haven't seen my card go past 50c at full load.
i guess it's ok, seems to work aight... gonna oc it some this weekend and see how the temps change then..
you can run only cpu apps and it wont hurt your folding a bit. Now if you run any Gpu apps, they will fight for priority of your gpu and will kill your folding points. I suggest to run cpu only if you want to do both.