Is a voltage stabilizer necessary?

I have a 1976 Santana 109 that I'm in the middle of rewiring. I've searched the internet and gotten some mostly useless information about the voltage stabilizer. Most comments say that it's not needed because the regulator does the stabilizing, but one said that the stabilizer drops the voltage to 9 volts for the fuel gauge and coolant temperature gauge. I've ordered a triple gauge package that includes a water temp gauge, but it doesn't require a stabilizer. Possibly built in. Anyone come across this problem and have some wisdom on the subject?

I have used the voltage stabilizer on my 2A when I rewired with new harness. Gas gauge and temp, I do believe need that in order to maintain the 9 volts. cheers.