My recommendation would be to go with the H-sport bar. You are then able to try both settings to see which one you'd prefer. With the OEM bar, you'll potentially be stuck with a bar that could end up not providing enough understeer reduction.

 

I just installed mine today. It took me, an amateur, a little over an hour from start to finish. Unfortunately the 15 degree F weather slowed me down instead of speeding me up, so I warmed up a bit before taking it for a drive. But once I did take the car out it felt great. The steering was lighter at almost any speed and the previous body roll was mostly eliminated. The increased tendency for the rear to swing wide is definitely noticeable on snow, especially when braking in a turn (a bad idea to begin with). This was the first modification I made to my A4 and I am very glad that I did it.

 

Is there any downside to doing this modification? (Damaging the stock suspension?)

I have a 2005.5 A4 with sport package and I have only heard great things from any B7 A4 owners who did this modification.

I was considering going for the S4 bar instead of the RS4 just to stay on the safe side.

Thank you for your input. (Sorry for brining this thread back... search button )