Can i install the BFX 2.2 mod while using the convo pack and dark times? or will that be too much?

If you use the Convo Pack 2.2 (which cuts back on alot of unused missions), then you should be able to fit all three with a little extra room for a custom map or two. If anything, you can make an "addon2" folder and just swap out mods back and forth from your addon folder when you want to play them.

thx mate

EDIT: i read on filefront that Kit Fisto is removed in BFX, does that mean if i dl it that he will also disappear totally ? or only in BFX mode?

Only in BFX. The only way two different mods will ever affect each other is if it states it in the readme (such as "if you have Dark Times installed, the Dark Times era will appear for this map") or if they have the same 3 letter addon folder, in which case they will conflict and most likely screw each other up.