Cow Magnets:
the original theory on these were that taping them to a fuel line 
"polarized" the gas and resulted in a miracle increase in power, gas 
mileage, and hair re-growth.  there's one born every minute.  BUT 
fuel line magnets DO have a legitimate use.  they DO trap rust 
particles traveling thru the fuel lines that can clog injectors, make 
carb needle/seats stick open, etc.  and hence performance and mileage 
may increase, tho not from "polarization"  Tomco, a major carb parts 
supplier sells strong magnets that stick to the bottom of the fuel 
tank to trap rust, also make one for the fuel line.

Bosch Platinum Plugs:
the application # for the wasserboxer lists a resistor plug.  you 
already have resistor wires and shouldn't be using a resistor plug.  
if you have wires, cap, rotor in marginal shape the additional 
resistance very well may cause problems.  on my '85 i couldn't run 
Bosch resistor platinums but i know others that have.  cut your 
frustration and install Bosch W7DTC 3-prongs.

Dansk aftermarket exhaust:
Dennis mentioned to be sure and get the support brackets when using 
the aftermarket.  the Dansk system i just put on mine (complete from 
header to converter) had all the necessary brackets already included 
and had an additional brace welded on that the OEM doesn't have.  
great system.  good price.

-dan