I'm a proud owner of a Peugeot 406 Coupe 2.2HDi - 2003 model. This is one of the most beautifull and confortable car to have. It is usable in everyday life... and now with improved performance!

-PSI powerbox since 35.000km (currently 100.000km, no black smoke, no problems at all). The engine is quite overengineered for the stock 136Hp, and mine should now be around 170hp / 380N.m (PSI anounced performance, not yet measured on my car)
-K&N replacement filter
15.000km between oil changes (BP Visco7000 Turbodiesel 0W-40)

I'm looking for someone who has changed the position of the air intake, from engine bottom to the front ("RAM" intake).

The stock variable geometry turbo allows for very good torque since 1000rpm. I am able to drive in 5th at 50km/h, and if I hit the pedal, the car responds imediatelly. In my last 1500km trip (mostly highways, with A/C on), the consumption was 5,8L/100km @ average 110km/h
However, the top end is quite weak. In fact, the 5000rpm mark is useless, because the peak power is achieved at little above 4000rpm. Anyone knows how to improve the top end power of my ride? I would appreciate sugestions... Thanks!