i m plnng to buy this game but my friends say that its gonna be relli tough..so will there be any form of difficulty adjustment in Mass Effect?

In KOTOR you could switch difficulties right before hard parts, but if you were good at upgrades and equipment choices and you were a high enough level you could never have to change it from hard mode.

At least it isn't like Oblivions slider, KOTOR was actually difficulty levels which, in my opinion is more straightforward.