Your GT3, pulls oil from the tank so fast, it creates a vacuum on the block and keeps the engine from leaking everywhere. Porsche Motorsports made 8-10more hp by changing the rear main seal on your GT3 engine.. you know why? That seal let the engine breath. The vacuum from the oil tank was so great, that it actually caused the rear main seal to collapse!!
We have no mechanical vacuum on the Boxster engines..
B