[aerohead]

Originally Posted by ademonrower

Many thanks for those very useful pieces of advice.
Re (from funkhoss):

Aux. vacuum canister for servo brakes: great! that sounds quite simple. Where do I get one?

A kill switch (you don't want to use your keyed ignition switch to shut off the engine); >> OK, I'll look into that
a manual transmission (for bump starting); >>yup, I have a man.trans.
manual steering (for obvious reasons!); >> yup, I have man.steer.
a deep cycle battery (EOC will ruin a standard lead-acid starting battery pretty quickly); >> many thanks for that advice: I was on my way to destroying my lead acid battery; and
an electric pump for the heater core coolant circuit (if you like having consistent heat in the winter!). >> I'll try to weather that one (no pun intended), but perhaps my passengers won't like it, so advice gladly accepted :-)

From aerohead:

* How will you be driving the car? >> mainly highway and uncomplicated country roads, typical speeds between 40 and 70 mph.
* Overall driving speed may determine where to focus your resources.
* And there may be legal constraints in Germany for some body modifications, which would not be a consideration elsewhere. >> Yes, that IS a problem: it's a pity that one is allowed to do so little to one's car here in Germany, but with a bit of cunning, and making absolutely sure that it's rock-safe, I reckon I'm on the "good" side in terms of practical measures. If I'm caught, then I can turn it to our (eco-modders) advantage and call a journalist that I know: she'd probably love the story and its environmental implications :-) I can't be caught too much though, because the fines would ruin me...

Thanks!
Looks like we need to discuss aerodynamics, so I'm going to move my response over to the Aerodynamics Forum, where your 'flow extender' thread is.
See you there.