--How old is the game (english version), and will thier be a lot more features added in the near furute?
Almost a year, including the betas. And yes, since the japanese version is still releasing stuff.
--What are slots, when i click on a part some of them have some square slots, what are they for?
Slots are for tuning, this is where the parts' stats are increased by using the Cosmo Pot at ground level. Each slot can be used to tune once. Note that the tune has a relatively high chance to fail, and when that happens, the slot is unuseable and no bonus stats are added.
--What do colored parts mean? Not read/blue representing weapons that come with the part. But some items text may be in light blue or red/ usually white. Does the color of the text indicate rareness?
That is an indication of how many slots are on the part methinks. this is only for dropped or reward parts?
--How can you tell if an item is rare?
Not sure if you can, I least i cant. You could always ask people.
--Can you trade with other players?
In the japanese version you can, but not here (yet)
--Is there a detailed item guide anywhere? a place or website where i can veiw all avalable items in the game?
Unless you can understand japanese, i dont think so. the current english wiki is still relatively incomplete.