as we all know rust is a chemical reaction. the oxidation of iron. i cant see how electrically charging a car can inhibit this. maybe im wrong but i dont think so.
i agree, there is not much difference between webers and Su's when they are working flat out. Constant velocity carbs (SU's) love full throttle, however the webers in my opinion are far more responsive and deliver more power through the entire RPM range.
Whats the prob with the 42's. What jets and venturies are you running. Be specific. emolsion tubes, mains, air corrector, pump jets, idle, pump jet with exhaust orriface (located in the bottom of the fuel bowl), main venturi and auxillary venturi
What CC is your engine? What RPM (be realistic) do you want to run the engine at? and finally tuned for power or economy.
Hopefully i can recommend some jets, that will suit your needs, at least a starting point
I have alot of info on jetting webers. I have this great jetting table from weber.
The right jets can make the webers work like a dog or go like a rocket.