roastbeef wrote Adding front bar will increase understeer. Are you sure this is what you want?
A front bar will feel flatter and more planted on the street, but might not produce the desired effect on the track.
I'd say this is true, except if he's on stock springs (or a mild lowering spring). Then a front sway bar can help get you more front end grip just by limiting the camber loss mid-corner. I did this on my 128i, and added on the adjustable Hotchkis M3 bar and it helped on track. But, that was with some Eibach off the shelf lowering springs, so still very soft rates.
Otherwise, yes. If you already have a coilover setup with decent spring rates, adding on the front bar alone will just make the car understeer more.