I would go FI... tolerent to different blends of gas, altitude and temperature. Thats the biggie. Another mile per gallon or so is a nice bonus.

I think the stock style 90's FI is now tunable. You can probably find somebody to help with a custom tune on a Magnum based engine if you step up the power a bit. FAST EZ EFI would be a good choice also.

On the fuel smell, if its coming from gas boiling or evaporating out of the carb, FI would stop it. If its caused by venting, maybe not. Vapors from the vent don't usually make a big stink so likley FI would fix it.