The cables are insulated, so there's no problem with them touching other components. You should be able to bend the PCIe power cables enough to get the side panel on. Either that or it will bow out slightly from the cables (not a big deal).
As for the fans, yes the i30 is enough to do some overclocking. I'm not sure what you mean when you say that you can't put the rear fan back on? It just screws in.
I tried to screw it back in but everytime i apply pressure its going in slanted, tried every possible screw with same result. The funny thing is the screw that came with it are the ones that are not working too as mentioned in the previous sentence.