So finally, I didn't give up analysis, and I would say I prefer Ra4, still, because we can get one pawn more, put back our White bishop in the attack, and we avoid to liquidate everything towards drawish endings.
30. ... Ra4 31. Kb2 (much better than the bad Nc1 that I mentioned before).
Then two possibilities (if we just play Ne4 then, it does not really makes sense, we just improved a bit his situation, so I do not mention this):
31 (A). ... Rxa2+ 32. Kc1
31 (B) ... Nxa2+ 32. Be4 and our situation is pretty bad.
So (A) is the solution if we chose 30. ... Ra4.
I see then three average,possible, moves.
32. the expected 32. ... Bf5 threatening c2.
and the two other possible moves (since we have to move our white bishop): 32. ...Be6 attacking the Knight,
32. ... Ba4 attacking the Knight, but also threatening the c2 pawn, whenever he moves the Knight.
what maybe expected is B d4 to exchange our dear black bishop. and going to soso ending.
so it might be worth considering the more interesting
32. Bc5, preparing Ne2+. at least, he cannot play Bd4 anymore...
Here, having a positional look at the situation (and I know it is not enough), I think it is good : we have one bishop and a pawn for one rook, and definitely a more offensive position. It is also more funny than the drawish Ne4 (though it definitely needs more investigation). and his plan is not clear at all (he has to liquidate, but how will he do that??). Finally, by going on the fight, we win the psychological battle