Koenigsegg Regera is way to overpowered and gives unfair advantage!

Agreed, even the rest of the 399 max cars can't keep up, aside from one, which is perhaps even more overpowered...

Some people say it would be unrealistic to upgrade a Skyline or Evo to compete with a Regera...

It's unrealistic to be able to upgrade a Regera in the first place!

On top of that, this shouldn't be a case of "Realistic is better", rather it should be the classic case of sacrificing reality in order to make the game better. After all, Need For Speed is arcade. Starting with the second NFS game, features were generally only made realistic if it improved the game / added onto the feel they were going for.

Well Balancing is a Dificult thing, if you would be for Reality there should no tuning at all wich would leave the regera even more powerfull.

On the other hand tuning makes those "weak cars" very strong.

There is competition for it on semi to full technical tracks the problem on high speed tracks is you can't say nerf the regeras top speed by much or push the other cars top speed that much, the regera is slightly balanced for its top speed because everey top speed part only gives you +2 instead of +5 kph.

Also was it ever a different thing ? In Drift its like there is only 1,2 Cars that are Competitive, in Offroad it seems Similar..

Even in NFSMW was there a balanced loadout ? for me there was the Elise wich was so so Strong because its Superior handling it would crush the high end Competition because of that..

I can understand you as One  that might not like to use the Regera but was it ever differently ?