IMO the common shaft stuff is ok to a point. When you get into those kind of spring pressure I don't think I would go that way for sure. I have used common shaft stuff with open pressure around 850 not sure I would want to go further than that. From my experience anything above that and you will start to see issues with breakage. While I do not have any first hand experience I have seen it on a number of other combos. When you throw in the turbo think then IMO you need to go with the best possible parts and methods. The added pressure/heat on the exhaust side would want me to go wit paired shaft set up and pushrod oiling. IMO the only thing spray bars are good for is valvespring cooling and some added life there. Not to use as a primary method of oiling a pushrod cup.