[Finnster]

You may want to look into getting fixed rear hubs, like integy makes. Then you will not have any possible camber issues in the rear making it less stable in the back. Even with my setup board, it was always had to get the rear perfectly aligned as there is quite a bit of slop in the stock setup. The ballends are soft and tend to bend and stretch easy, making the whole rear sloppy.

The longer length should make the truck easier to control in the air, and less sensitive to thr input. EG. my crt.5 is very short WB, corrects very quickly in the air, but v easy to overcorrect or get thrown off balance. Much more difficult to control the car.

If you have more power or heavier tires, you will get more responsiveness to thr corrections in the air. Can be a matter of thr control off the jumps as well.

Personally I have not had any probs w/ the ext axles in my XL. I have 40 series offset wheels as well. My bearings are still the orig bearings that came on the truck and roll smoothly after 2+ yrs of use and good care. I would not trade off the stability and looks you get from the wide stance for any small increase in durability or turning radius.
As mentioned, the threaded portion seems the most common breakage, and is still there on the narrow axles. Its not the way I would have designed the truck, much prefer a wider arm and a trug style axle, but it is what it is.

I would say stick with it for a while and work on the setup and technique before you rip the whole thing apart. I never liked the tire choice tho. Most OEM tires are crap anyway. I would always recc some Proline tire instead.