I hear the LS water pump gives 131% more coolant flow than the GSR. The LS pump has a smaller gear and the Gsr has a larger gear. I heard use the ls pump if your not using a vtec and if you are using a vtec head than get a vtec pump even though the ls pump flows better to an extent. The reason the GSR pump is larger is because to reduce cavitation and its says cavitation can stop coolant flow or create bubbles, so they made the gsr pump larger to reduce cavitation. I'm not 100% sure about all this but this is what I read. Well if I were to be boosting the ls would I need the ls or gsr pump? I will not be revving as high as the gsr, only the oem spec for the ls which is 6800 but since ill be reaching my rpms faster, would I need something larger diameter gear to reduce cavitation or do I not know what im even talking about?