I can attest that the longer arms are nice. They are very sturdy. I only installed the passenger side one. It was a huge pain in the ass but it helped tighten up the seal on that window and completely killed the wind noise.
I highly suggest examining the longer arm when you get it and look at how it might fit prior to taking the old one out. There are tabs that fit into little holes on the existing mounts. Be very careful with the existing mount and do no break it. Possibly use a heat gun very slowly to warm up the plastic so it is more manageable.
If you end up getting them and have any questions, post up or throw me a PM.