Volkswagen Bora/Jetta workshop manual 2.0 2004

Please, I would like to know if someone can facilitate the workshop manual for the Bora (Argentina) or Jetta (Mexico)
Motor Naftero 2.0 year 2004.
In particular, I would like to know if there is the possibility of changing the ratio of the fifth march, for one that Volkswagen recommends and with original spare parts of the brand by which it makes it possible that the engine works less than less, (if possible 500 less). KMT/h at fifth speed, the RPM marks 3500 laps and I consider that it is very high for a 2000 cc engine.
I also wanted to clarify that my speed box is the EZK version whose fifth -speed ratio is 36/43.
Of course, I appreciate your gentle collaboration.
Greetings
Tito.