In Winter I wouldn't even run the hard arms. Go with the normal arms. Should be alright in every situation. The front arms are a bit weak (it's the design of the car), especially near the hinge pins, but it's not that bad. I broke more front arms on my B44 years ago. They broke by just looking at them.
To answer the original question: no, there is not company that makes better arms. Yokomo is not a brand that has a lot of aftermarket parts available.