Depends on how you build/engineer it. The Dolphin handles heat pretty well, so instead of maxing speed, I (usually) go for range and minimal heat. i.e. clean drives and low emissions PP. Still boosts around 450 m/s (with a good G3 roll - a very good G5 DD roll can give you 550) and with an engine focussed PD, can keep that up pretty much all the day. The only time the cops can get you is when landing at a planetary base and you don't keep an eye on the comms

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Main profile is long range passenger or rares/small cargo transport, though (or exploration). Wth a small additional fule tank, you can do 200+ ly without refuelling, with a scoop you can refuel at max intake without overheating, or even reaching 70%.