The trick with an air/air is routing the 3 inch tubing back across the front of the car to the intake. It's much easier to route 3/4" coolant hose. The air/water also should give less lag because there is only about 6” of tubing needed.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine