i wouldnt worry about any galvanic corrosion unless you plan on putting pontoons on your car and using it as a boat. but you are right-disssimilar metals will react quicker(under the right circumstances) one metal becomes the "cathode" (titanium,because its harder) and the other(aluminum) becomes an "anode" and will begin to pit and corrode.but again unless you race you car under salt water it wont happen. oh and BTW thread lock is a corrosive and damages aluminum