I also agree it will open a little earlier. Enough to be a problem is the unknown. You certainly would not want to mix injectors with large differences of pop pressures for example. A milli volt test with each type in operation might clue you in. It could also change the idle speed of the engine. You are also playing with the design paremeters for the engine to some extent. Personally I would not do it. Now if nozzle flow rate is the same they might be recalibrated by a shop to the higher pressure if they are the same internal design as the turbo injectors I imagine. A injector shop would know.