Driveshaft

My Dusters driveshaft formally pulled family duty on a 4 door fury, at least the grease pencil on it says so. Someone had it cut to size and welded, only thing is sounds like its full of sand, assumeign its the welding slag, car gets a nice harmonic vibration at high speed and sure all that slag isn't helping. For a mild 340 street driven is it worth it to go aftermarket aluminum shaft or just a stocker?