i run mine back to the sump.i have a smooth torque performance tank on mine, it has a drain at the bottom,then about an inch up from that there is the drain to sump. the 2 pipes are seperated by a baffle. so when i drain mine there is water in the bottom section, the oil is kept seperate from the water, water is heavier than oil, so it sinks through the oil to the bottom the baffle stops the oil mixing with the water. the bottom section holds about a litre of water, so in winter i drain it about once a fortnight, in summer its fine, as rob says the heat of the motor drys it out. on track my 30 can put 2-3 litres of oil through it, but as it goes back to sump its fine, lets face it on track the oil in the tank is the same as in the sump when hot. on the road the car puts no oil in the tank at all. the tank has a screw cap to allow you to look inside to see whats happening inside.no issue...bernie