should i buy a low profile servo to use in x6
 

as above. my theory is that a low profile servo will leave me with more room at the back to put weight rather than have it all stacked up on top. was thinking about the savox 1251mg. any thoughts or recommendations?

You dont need a low profile servo but it does give you more space to add weight, so if your looking for a new servo a low profile one is a good way to go.
The savox 1251mg is a good servo and cheap at about £40 compared to the Futaba S9551 that I run!