Eddy,
Did you increase the size of your front bar? This was what I found and used when I was deciding on my setup. There are a lot of opinions and studies on this. I would probably talk to the manufacturer. I used option 3 because I increased the size of my front ones. So far no issues with my decision but everyone is different and uses their cars differently.
1) Increasing just the front bar, the front tires see a larger percent of total weight transfer which increases front tire loading and reduces front tire grip slightly (and also the opposite effects on the rear tires)... BUT you also get a reduction in roll which reduces how positive your camber goes in hard cornering for a large increase in grip. The end result is a good increase in cornering grip with perhaps a very slightly higher bias towards understeer. Now, before a thousand people jump on that last statement, let me explain. I know that people are also putting on big front bars and saying "I got less understeer". I would contend that what their butt-dyno is telling them is not the whole truth. The real story is, the increased grip (from roll reduction) allowed them to go faster in places where they previously had understeer. So yes, perhaps they experience understeer less dramatically than before, but the bias has still shifted towards understeer more... it's just that the limits are now significantly higher so this bias is less apparent. I'd say that the front tires see a moderate gain in grip while the rear tires see a significant gain in grip.
2) Increasing just the rear bar, the rear tires will see a larger percent of the total weight transfer which increases rear tire loading (conversely taking load off the front tires) so you get a slight reduction in rear grip and a slight increase in front grip for a more oversteer-biased setup, but the decrease in lateral roll also increases total grip, just like above. The net change is more grip, more oversteer. I have heard a lot of people say "a rear bar increases oversteer by reducing rear traction". This is not exactly right. What it is doing is taking load off the front tires, thus increasing front traction where it is severely lacking, AND increasing load on the rear tires while also reducing roll. I would say that rear traction is increased marginally overall, while front traction is increased signifcantly.
3) Increasing both bars, you get double the reduction in roll and no real change in bias. This is the way to go, IMHO. You don't change the overall bias of the chassis, but you do vastly increase grip on both front and rear tires. I'd say that both front and rear tires see a significant increase in grip.
