Retuning the factory ECU has pros and cons. Pros: everything is in one package, OBD-II parameters should remain, uses OE sensors so replacement should be no problem... Cons: can't revert back to stock in a pinch, limited number of reflashes before ECU becomes unstable, must reflash after any big future mods, user tunability still questionable.
As for street cams -vs- club spec I've driven both and the club spec are very potent at higher revs. The street spec give you power everywhere and are designed for stock redline. If you think you may do headwork, valve springs, raise redline etc in the future go with the club spec. If you may go turbo or s/c, keep stock redline, etc go with the street cams.