Actually, I find the stock skis to be just fine. I played the "sink your bucks into skis" game many times on previous sleds. Given the conditions that I ride in and type of riding I do, the stock ski works great. If I did more powder, etc, I would again consider a possible switch.
But, ... When I went to Dual Carbides, which has a curved support bar, I regained the arch in the ski that I lost when I had a singe runner. The Dualies are fairly stought and re-acrched the ski. I hated the previous set of 6" carbides beacuse they were too hard to steer. I wanted to go to 8", but, did not want it to turn even harder. So I went with 4" Dualies. BTW, with the Dualies, you can turn the bars fully, on concrete, with a finger pushing. With the 6" singles, you had to really reef on the bars.
So, I believe that the right set of bars can arch the ski. Personally, I think the arch is desirable, especially with reverse.