I just made my Platinum Haunter to evolve...

It goes from :

Haunter lvl 62
Max HP : 151
Attack : 79
Defense : 84
Special Attack : 185
Soecial Defense : 84
Speed : 153


To

Gengar lvl 62
Max HP : 170
Attack : 96
Defense : 102
Special Attack : 205
Soecial Defense : 109
Speed : 172

Which means :

Max HP : +19
Attack : +17
Defense : +18
Special Attack : +20
Soecial Defense : +25
Speed : +19


This means : Even if you hate Gengar and that Haunter is one of you favorite Pokémon, MAKE THEM TO FUCKING EVOLVE. End of the story.