getting a 8350 soon with stock cooler but just wondering if i was to get a better air cooler or closed water cooler system and overclocked it would it make much difference ?
It depends on how much you want to spend and what your case supports. On the lower priced range air coolers usually do a better job than water cooling at a similar price. However, ones you start getting to the more expensive coolers they are about the same with maybe a slight advantage to closed loop water coolers.
Look how much room you have in your case and how much you want to spend.
cheers the case is a bit cramped i have to say i have seen some air coolers that are huge will probably have to move computer aswell as not much airflow around it
what about performance increase with a modest overclock would it make that much of a difference though ?
For the price the Hyper 212 Evo will be the best until you hit something along the lines of the Noctua NH-D14 and other similar coolers of that kind where you actually notice a difference in temperature.
Closed Loop cooling i would suggest only the high end ones because air cooling pretty much beats anything below them. Something along the lines of the Corsair H100/100i/105/110, CM Glacer 240L/360L (Swiftech h220 replacement IMO the best AIO cooler but pricey).
Though there's many factors into play so i would personally say that unless you're going to drop in $100+, liquid cooling isn't worth it and it's better to save and go for air.