Mate i get alot of powder coating done for people and never had any think crack. The one thing if you have had the bits you have had done and anythink engine related is to make sure they have not ahot blasted the inner of the rocker cover if so clean it out good and proper other wise your engine will have sand round it which will block oil ways pump etc. clean inlet and fuel rail out to brake cleaner is good to wash out with but make sure its done well Hope this helps