Borrie, do you know what injectors you have now? Bosch part number 0 280 150 357 is typically found in 740s and 0 280 150 804 is found in my 760. At least one "Specifications" book from Volvo says that the 357s flow 300 cc/min while the 804s flow 285 cc/min. HOWEVER, every other resource I've seen on the internet shows the 357s at 300 cc/min and the 804s at about 337 cc/min. In any event, I'm running a measured 16 psi, and based on measurements of the oxygen sensor voltage (high .9s), the injectors are still keeping up. The only other engine modifications are a Unitek cam and modified airbox. Having enough fuel is important but you might be able to save some bucks.