Ahh... I truly can't understand the complex world of the EV's (or DV's), so I'll provide a site that seems to.
Effort values in the Pokemon games are base stats that give bonus points to an individual Pokemon's stats depending on what kind of Pokemon they defeat to gain experience from. After a Pokemon reaches level 100, it may still gain Effort Value points up to 65535 in each stat.
The speed of your Latios is likely not going to be the same as the Latios owned by, say, a person across the room who happens to also have a Level 100 Latios.It depends on Effort Values and Individual Values. It's hard to explain, but these values do effect your Pokemon's stats, regardless of what kind it is, which is why, for example, two level 100 Raichu of the same gender will most likely have different stats.You can maximize the speed of your Pokemon (in this case, your Latios) by giving it Carbos and fighting Pokemon which give Speed Effort Values (EV's). For a list of these Pokemon, run a search using your favorite search engine. I'll even provide the keywords: list of Pokemon which give speed evs
No it does not matter.
EVs stand for Effort Values. They are how much of a stat your Pokemon earns when it levels up. If you wish to work on a single stat, fight certain Pokemon. If you level up by fighting a lot of Starlys, you will get lots of the speed EVs, giving your Pokemon more of the speed stat. Those items like Proetin and Iron also give you EVs. If you EV train your Pokemon a lot they will become very powerful.
It doesn't matter what level your Pokemon are.
Effort values, or EVs, as they are most popularly called, represent how hard you personally work trying to train your Pokemon. They improve your Pokemon's statistics by a small percentage, depending on how much you work yourself. If your Pokemon gains a level by competing in battles, it will gain more EVs than it will if you use a rare candy or if you put it in the day care.
It does not matter where you level it up.
doesn't matter.
You don't need to beat the Pokemon League to get Pokemon up to level 95, just keep grinding on wild Pokemon or Trainer battles. You will get experience from them no matter what level.
you have to use a dusk stone. Level doesn't matter
Tyrogue evolves into hitmontop at level 20 if its attack and defense stats are the same. One way of making sure this happens is by using protein and iron to modify the effort values (EVs) of your tyrogue.
it doesnt matter what Pokemon you use, they are all the same level if they are over level 50. so choose you top-levelled Pokemon for it.