I consider people who make outrageous cheat vehicles "hackers." I consider people who make harmless vehicles meant to be fun, look good, or correct an engine sound to be "modders." "Hackers" have a negative context so I use it to label the negative group of people. "Modders" do have a negative context, but it doesn't sound as serious as hackers do.
I really hope the stigma of modders ends soon. It's really getting on my nerves seeing so many people vehemently against modded "for fun" cars. I think a portion of the hatred comes from people that never got their own custom cars.