Hot Rod's personality didn't change. He was neutered at 6 1/2 mos. He didn't gain any weight, well he was just under 3 lbs at his neuter, he's now 4.7 lbs at a little over 2 years old.
He had 14 teeth removed at the same time.

He was out of it for the most part for about 3 days after but was back to his ol' self. Good luck with your little one. He should do fine.