Yes, the GSS-342 is the 255lph pump, and I *think* it is the high pressure one as well. It's not necessary to have, but like his FAQ says on that page SAK posted, if you want to go faster at some point in time in the future and you buy a low end pump, then you'll just have to buy a high end pump later down the line when the pump becomes the bottleneck and/or your fuel pressure is ramped up so high that the pump eventually fails.